


Possessed

by DeckofDragons



Series: Possession [1]
Category: Luigi's Mansion (Video Games), Super Mario Bros. (Video Games)
Genre: Also almost forgot to add:, Angst, Attempted Murder, Blood and Gore, Booigi, Gen, Ghost Possession, Gooigi is still in the background doing their thing, Gooigi makes a couple appearances, He doesn't get one, I'm just having fun, I'm not even sure how much sense this makes, Luigi gets a hug, Luigi has a real bad time, Luigi needs a hug, Mentions of drugs and alcohol, More Luigi having a bad time, Some weird soul and ghost stuff happens, Violence, attempted murder that looks like attempted suicide, even worse than before, tags for part 2:
Language: English
Status: Completed
Published: 2020-08-05
Updated: 2020-08-29
Packaged: 2021-03-06 01:20:24
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 12
Words: 28,571
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25724995
Author URL: https://archiveofourown.org/users/DeckofDragons/pseuds/DeckofDragons
Summary: Part One (chapters 1-4): King Boo has a new plan for defeating Luigi. It involves possessing him and dragging him around in front of his loved ones for amusement.Part Two (chapters 5-12): King Boo may have made a big mistake. Luigi pays for it the most.
Relationships: King Boo & Luigi, Luigi & Mario (Nintendo), Professor E. Gadd & Luigi
Series: Possession [1]
Series URL: https://archiveofourown.org/series/1915030
Comments: 68
Kudos: 123





	1. Possession

**Author's Note:**

> I've become quite fond of the 'King Boo possessing Luigi' concept, especially with all the angst potential it brings with it, so much so that I became filled with the intense need to write a fic about it and so I have. This is also my first fic for the Mario Bros. fandom and it's honestly one of the angstiest things I've written in a long time which is not what I would've expected my first fic for this fandom to be but it was a *lot* of fun to write. Enjoy! :)

Luigi wasn’t sure what woke him but something had. Sitting up, he looked around the room for it. He’d fallen asleep on the living room chair again, watching TV. It was off now though, so were the lights, only the moonlight flittering in through the window allowed him to see that the room was empty.

With a hand that was only slightly trembling, he grabbed the remote from the coffee table and pressed the power button because if he’d fallen asleep watching TV it _should’ve_ been on. Nothing happened though. Pulling on the switch for the lamp next to his chair also did nothing. … The power was out. … Was that what had woken him?

The power going out was a fairly normal thing. It happened sometimes and was nothing to worry about, it’d probably be back up soon. … But _why_ did it have to happen in the middle of the night? It was too dark!

Gritting his teeth, he forced himself to stand and start carefully making his way towards the hall. He was going to go to bed and sleep and not be afraid of the dark. Even if there _could_ be ghosts hiding in it there probably weren’t and even if there was, he’d defeated more than enough ghosts by now that he shouldn’t be afraid of them anymore. … He still _was_ though because his brain apparently wasn’t into the whole being logical about this stuff thing.

He paused upon reaching his bedroom door. Thankfully it was the first door near the start of the hall because it was _dark_ further down with now windows to allow moonlight to leak in. It was like staring down into an abyss, he _hated_ it.

“Puppy,” he called down it anyway, lifting his voice as loud as he dared. He braced for Polterpup to race out of the darkness and jump him but nothing happened. Normally a single call was enough to get him to come running, apparently not today though. He was probably out back, digging holes again. Luigi should go stop him because he wasn’t supposed to do that but… he’d barely made it to his bedroom door, no way did he want to go all the way to the backdoor, outside, and then all the way back here when it was so dark. … He did have a flashlight in his room though so…

Turning back to this bedroom door, he opened it and… screamed. King Boo was waiting just inside, grinning wide and laughing. Luigi only managed to backpedal a few steps as the light in King Boo’s crown grew and then with a sound much like a thunder clap flashed, replacing the utter darkness with blinding light. There was a vague sensation of falling as something pulled Luigi’s consciousness down. Something was terribly wrong about that but…

He came to laying on the floor, facing the ceiling. It wasn’t completely dark anymore, there was a light coming from… somewhere, it had a purple tinge to it. That was odd, what was…

King Boo’s laugh, though very similar to other boos’ was still distinctly his and unmistakable for anything else. Luigi screamed and… nothing actually came out of his mouth, nor did his body move to scramble away as he oh so desperately wished to do. More laughter from King Boo.

‘ _This worked so much better than I thought it would._ ’ His voice came from inside Luigi’s head. How? Why? What was happening?

Luigi sat up but much slower than he would’ve liked, his face twisting into an evil grin. He looked down at his hands, flexing them and closing them into fists as if he were working out stiffness. He wasn’t in control of this or himself in anyway. But if he wasn’t in control of his body than who…

“I am,” King Boo said out loud, using Luigi’s mouth. It was a horrible, gross, _awful_ realization that would’ve had Luigi shuddering with revulsion and horror if his body were still his to control. This kind of violation was something beyond anything he’d ever even considered a possibility let alone something that someone would do to him.

King Boo laughed as he stood up and stretched. An echo of his glee about a plan of his finally be successful hit Luigi, making him feel almost sick. Which only furthered King Boo’s delight. He took a breath as if to say something, probably a taunt about Luigi’s revulsion and horror but a sound drew his gaze to the left.

It was Gooigi. They’d come out of their room and was now staring at Luigi and King Boo. Their face was nearly expressionless as always so what they felt about whatever it is they saw was impossible to guess but Luigi wanted more than anything to beg them for help. It… didn’t seem to be coming though.

King Boo grinned and took a menacing step towards them… or tried to. He stumbled instead, landing face first on the carpet. Even though it hurt and despite the circumstances it was kind of funny; big bad King Boo couldn’t even walk properly.

‘ _SHUT UP!_ ’ King Boo shouted internally, making Luigi do the mental equivalent of a flinch, all mirth gone from the situation. ‘ _It’s not my fault you’re stuck with an inferior way of moving around. I can_ fly _remember? I don’t need legs._ ’ He pushed himself back to his feet and brushed himself off. “What are you looking at?” he said in an almost growl as he glared at Gooigi. “Go away.”

Gooigi stared for a few seconds more before switching their flashlight on. They flashed it but that did nothing but hurt Luigi’s eyes a little. It didn’t seem to bother King Boo any as he tried walking towards them again, this time with more success even if his balance was still very off. Gooigi responded by switching to the dark light which was normally effective against both boos and possessed objects but… seemingly not this time.

Before they could attempt anything else, King Boo was in front of them. He spat on them and as always when even a drop of water touched them, they started melting, making a vague ‘uh oh’ sound. They’d ultimately be fine and would reform in their tank but watching them melt was still unpleasant. … And with them gone, there went Luigi’s chances of immediate rescue because he’d never gotten around to having E. Gadd modify the tank so Gooigi could get out on their own.

“That takes care of that then,” King Boo said with a satisfied simile as he turned away before Gooigi was even all the way melted.

 _W-what are you going to do to me?_ Luigi dared to venture at him, his inner voice quivery with fear. He wanted to be angry and he should be but… anger was hard even when he wasn’t terrified.

King Boo didn’t respond with words of any sort, just a spike in that echo of his evil delight as he started making his wobbly, careful way further down the hall. The purple light coming from somewhere on Luigi’s person wasn’t much of a light source, it barely illuminated anything but it was better than nothing. Though when they reached the hall mirror in a few steps, Luigi would’ve preferred it not be there at all as King Boo stopped to look into it.

Luigi’s hair and mustache were now a stark white. His eyes mostly empty white except for a tint of purple around the edges; very reminiscent of King Boo’s eyes. The purple glow was from King Boo’s crown, it was smaller on Luigi’s head but still unmistakable as anything else. This… was probably the worst thing to ever happen to Luigi and that was saying a lot.

“I like it,” King Boo said with an evil grin that looked _wrong_ on Luigi’s face. “Your outfit is gross though; we’ll have to fix it before we go talk to your friends.” He pulled the hat off and tossed it aside so the crown would rest more naturally on his head.

‘Talk to your friends’, that could only mean…

“Yep,” King Boo interrupted the thought. “You really think I’d possess you and _not_ drag you around in front of your friends? What would the fun be in that?”

 _No, no, please no!_ Luigi hated to beg but he did _not_ want his friends to see him like this and… most of all he didn’t want _Mario_ to see him like this.

“Too bad! His reaction is the one I’m _most_ looking forward too. But before that, it’s been a long time since I piloted a meat suit, I apparently need some practice.” So he wouldn’t trip at a bad time again… if only Luigi could appreciate the humor in that thought.

A short time into King Boo’s ‘meat suit’ practice he decided to make everything worse by taunting him ruthlessly. Luigi did his best not to react because that’s what King Boo wanted. He was doing mostly okay at it for a while… until King Boo found a button to push anyway.

‘ _What do you think Mario will think of you when he sees you like this?_ ’

That… was a good question? What _would_ he think?

‘ _Maybe he’ll be happy._ ’

Luigi really shouldn’t respond but… _Why would he be… happy?_

‘ _Because, I’ve defeated him three times now. Each time you’ve had to save him. But normally_ he’s _the hero, right? And you’re just a sidekick at best. Thus, by saving him, you make him look like a fool. So maybe he’ll be happy to see you’ve finally been defeated by the one foe he’s never been able to best._ ’

Logically Luigi knew that couldn’t be true; Mario was his bro, he’d never be happy to see him like this. But… what if it was true? He’d never indicated he had resentment towards Luigi for having saved him three times now but what if he was just good at hiding it? Mario had always been better and stronger than him, it made sense he wouldn’t want to be saved by someone like Luigi, right?

‘ _Exactly! Heck when he finds out maybe he won’t even want to…_ ’ King Boo tripped over the coffee table, banging Luigi’s shin and landing on it hard.

Despite not being in control of his body, Luigi felt the pain just as strongly. It sucked but it did serve to knock him out of his spiraling worries. Of all times to worry about Mario possibly secretly hating him, now was _not_ it. He was _not_ going to let King Boo taunt him into worry about that.

With an annoyed huff, King Boo straightened and resumed walking practice, seemingly unphased by the pain. The fact that his coordination was so bad was the only mercy in the situation, hopefully it would take him a while to get past it.

Polterpup finally decided to return from outside a short while later, interrupting another taunt from King Boo. He froze, his glowing eyes locking onto King Boo and Luigi a half second before he started growling. Luigi had never heard him growl like that before, it made him want to pull back. But instead of course, King Boo approached.

“Go ahead, attack me.” He grinned as he held Luigi’s forearm out, the perfect target for a Polterpup to jump up and bite.

He looked like he was going to, rearing back ready to pounce, but faltered instead, his angry growl petering out. He barked and ran in a little circle a few times. When he stopped, he sat down on his hunches and whined up at Luigi rather pitifully. After a few seconds of King Boo waiting and probably hoping for him to attack, he barked again before turning and bolting back through the front door. Well… at least he didn’t attack so Luigi wouldn’t have to add _that_ to the list of traumatic experiences he was going through tonight. Maybe… he was going for help?

‘ _He’s probably abandoning you. But even on the off chance he does go for help, it’ll be in vain. You’re my hostage now and I don’t intend to give you up anytime soon._ ’


	2. E. Gadd

Luigi’s phone started ringing, the tone signified it was E. Gadd. … Possibly calling about King Boo’s escape, too bad it was _far too late_ to be of any warning to Luigi.

‘ _Oh! E. Gadd!_ ’ King Boo said internally, his grin spreading across Luigi’s face. ‘ _Let’s see how well I can impersonate you, huh?_ ’ He pulled the pone out of Luigi’s overall pocket. “Howdy.” Unlike the other times he spoke, his voice quivered a bit and well… he did sound a lot more like how Luigi normally talked. Not exactly but… the difference probably wouldn’t be very noticeable over the phone.

“Sonny,” E. Gadd said, apparently fooled. “I got news. First off, King Boo escaped again, whoops.” ‘Whoops’ indeed, if Luigi got out of this alive, he might be tempted to strangle E. Gadd for losing King Boo for a _third_ time. “And your dog is here. He seems agitated about something; he won’t shut up. You know what’s up with him?” He seemed more concerned about Polterpup than he was King Boo’s escape. But at least, Polterpup had gone for help, right? … Too bad he couldn’t actually tell E. Gadd what was going on.

“W-what do you mean King Boo escaped?” King Boo put way too much fake terror into his voice. E. Gadd _had_ to see past it and suspect something, right?

“I mean he’s out and about again, what else would I mean?” Apparently not. “He was there last time I checked but gone this morning, don’t know what happened. Hmm… actually that might be what your dog is trying to tell me. Maybe he knows where King Boo is! You should come over. Maybe we can find him again before he lays his next trap.”

King Boo’s grin widened. “O-kay, if you insist.” More fake fear, poorly disguising evil delight.

Luigi pushed against King Boo, trying with all his might to _say_ something, to warn E. Gadd. … He failed and with an internal laugh, King Boo hung up.

His stride much steadier now after a couple hours of coordination practice, King Boo started for the door as he repocketed the phone. Outside, the sun was starting rise, a testament to the hours Luigi had already spent trapped in his own body. It felt like ages though. He’d never been this tired before, he wanted to lie down and sleep for a year but instead, King Boo piloted his body towards his car.

‘ _I’ve never driven a car before so this should be fun._ ’ King Boo said as he got into the driver’s seat. Oh dear…

_If you crash, I swear I’m going to kill you._ Luigi was having a bad enough time as it was without adding ‘dying in a car crash’ to it.

‘ _Don’t worry, I won’t. I can’t have you dying on me before we say ‘hi’ to Mario after all._ ’ Oh right, that was a thing… maybe dying in car crash wouldn’t be so bad after all. King Boo’s only response to that thought was a laugh.

“The longer I spend piloting your stupid meat suit, the more I hate it,” King Boo complained about an hour later. “It’s gross and getting anywhere takes forever even with a car. We’d have been there _forever_ ago if we could travel my usual way. How do you put up with any of this without going mad or wanting to die?”

_Leave then if you don’t like it._ Did Luigi dare hope that all the inconveniences that came with a body might be enough for King Boo to abandoned this horrid plan of his?

“Nope, not happening. I can endure it to make you miserable, I just don’t understand how or why the living put up with it.” Well, that wasn’t surprising, so much so it wasn’t even really disappointing.

_Weren’t you alive once?_ Boos were a special type of ghost, right? So, even King Boo had to have been alive once upon a time.

“Yep. It was so long ago I don’t remember it though. Which I’m glad for because…” He made a strangled gagging sound, fully emphasizing his annoyance.

With an internal sigh, Luigi did his best to go back to zoning out like he’d been doing ever since King Boo taken a detour to the clothing store. He’d bought a fancy white suit that and purple tie that he said was far more fitting ‘gross overalls’. Which, with how his possession of Luigi affect his appearance, was true. He’d thrown Luigi’s clothes out completely.

E. Gadd’s lab was all the way outside of town and a fair way away from it, thus it was another hour before they finally reached it. King Boo pulled right into the driveway, parking very crookedly and just barely managing to not hit anything. If he had though it might’ve given E. Gadd some warning that something was wrong but… it was too much to hope for.

King Boo didn’t bother ringing the bell or knocking, he barged right in. The front door wasn’t even locked; E. Gadd could _really_ use some lessons on proper security protocols.

Inside, neither E. Gadd or Polterpup were anywhere to be seen. They’d probably be further in, in the lab proper with all of E. Gadd’s experiments. All this room had was his monitoring equipment. None of it was currently turned on which probably explained part of how King Boo managed to escape so easily and not be noticed until it was too late.

King Boo hated the place. His feelings for it were intense enough that he probably couldn’t have kept them from Luigi if he’d tried. He’d been held captive here three times so of course he hated it. It made Luigi even more nervous about this upcoming meeting though.

_Please don’t hurt the professor._ Luigi begged because there was _nothing_ else he could do.

King Boo ignored him as he strode in and towards the lab proper. His coordination practice was unfortunately very successful even after a long car ride. It meant if things got violent a trip or a stumble probably wouldn’t save anyone.

Polterpup’s furious barking was audible a second before he burst out of the back room and into King Boo’s path, blocking him from entering the lab. King Boo looked down at him, raising an eyebrow in annoyance. Thankfully he made no move to hurt him though.

“What is it dog- … Luigi?”

King Boo looked back up to see that E. Gadd had followed Polterpup out. As always, his large glasses made his expression hard to read but his mouth was set in a confused frown.

“You’re half right,” King Boo said, turning his evil smile onto E. Gadd. He hated him _almost_ as much as he hated Luigi. “But perhaps you might want to call us ‘King Booigi’ instead.” He laughed at his own bad pun.

E. Gadd made a wordless sound of surprise before ducking back into his lab. Hopefully he could flee out the back or… _something_. King Boo gave chase, stepping over Polterpup with ease because Polterpup wouldn’t attack as long as it would hurt Luigi too.

In the lab, E. Gadd hadn’t gone for the back door but a Poltergust instead. Dammit! … But maybe he could… It didn’t even turn on when he pressed the switch, making an empty clicking sound instead. King Boo reached him before he could sort out whatever the problem was.

_Please_ _don’t_ … Luigi’s desperate plea cut off as King Boo balled up a fist and punched E. Gadd in the face hard enough for it to hurt Luigi’s hand too. The sound of his nose breaking was audible, a wet crunch that sickened Luigi almost as much as feeling it give way beneath his fist did. His glasses broke too, bits of them cutting into his face and Luigi’s hand. He went limp and would’ve collapsed to the floor if King Boo hadn’t caught him by the neck.

_No, no, don’t, no!_ Luigi begged as he started squeezing as hard as he physically could.

‘ _You know the_ best _part about having hands? You can_ strangle _people!_ ’ King Boo’s glee and satisfaction was sickening but not nearly as much as the far too clear feel of E. Gadd’s pulse in Luigi’s hands.

His weak eyes fluttered open, focusing on nothing. He reached a hand up to paw at Luigi’s hands but there was little strength in it. His face was already starting to turn purple, his eyes bulging.

_Stop! Don’t! Please don’t!_ Luigi strained and pushed against King Boo’s control of him with everything he had. … Tears welled up in his eyes, blurring both their vision before spilling over and his hands twitched, loosening their grip slightly for half a second, allowing E. Gadd to take in a tiny gasp of air before King Boo pushed back, tightening their grip again. Luigi had done something but… it wasn’t enough… he couldn’t…

Something launched itself into Luigi’s side, making King Boo lose his grip on E. Gadd’s neck out of surprise and sudden lack of balance as something bit down hard onto his forearm. They fell over in a heap, the biter on top. It hurt bad enough that it took Luigi a few seconds to realize it was Polterpup. He may be a ghost dog but his teeth, though rarely visible, were sharp enough to punch through the suit sleeve and deep into Luigi’s arm, drawing blood.

Before King Boo could try to push him off or attack him in anyway, he let go and jumped back to stand in front of E. Gadd who lay on the floor, clutching at his throat as he gasped for air. Polterpup placed himself squarely in front him, growling protectively, his teeth dripping with Luigi’s blood.

Even despite the horrible throbbing and spreading warmth in his forearm as blood oozed from it, Luigi couldn’t help but tremble and cry in relief. Until King Boo put a stop to it though with an internal growl as he fully reinserted control.

‘ _You’re pathetic. I can’t believe I ever lost to_ you _! Crying and whimpering over a foolish old man who doesn’t even respect you._ ’

_Please… please don’t… hurt him… please._ Luigi lacked the strength to do anything more than beg. There was nothing he could. He was going to have to watch as King Boo killed Polterpup and then E. Gadd with his hands, meaning in a way, he’d be the one doing it, right? He couldn’t… that wasn’t…

‘ _First, Polterpup is already dead, I couldn’t kill him again if I wanted to. Second, I don’t kill dogs or any other animals, they’re too precious even if some of them are traitors._ ’ He glared at Polterpup.

… ‘Precious’? … King Boo had soft spot for animals?! What? … Luigi probably would’ve fallen into a fit of desperate laughter if he had the means to do so.

‘ _Everyone has a soft spot for animals, you fool! Even Bowser’s got a cat. I heard it had kittens recently too._ ’

“What do you… want?” E. Gadd said with a cough, his voice horse and barely audible over Polterpup’s continued growling.

With a huff, King Boo stood up. “If you free my boos and destroy all the equipment for containing them maybe I’ll you let live.”

“And Luigi?”

“He’s my puppet for now. You can’t do anything to me as long as he’s mine. Also, might I add, he’s still in here.” He tapped the side of his head. “Watching everything, _feeling_ everything. He was quite distraught when I was choking you. If only you could’ve heard his whimpering and begging. It was everything I dreamed it would be.” He allowed himself a small chuckle. “So, what’s it going to be? You going to cooperate or am I gonna have to kill you.” ‘ _The only reason I’m letting off for now is because of the dog. I’ll find a way to restrain him if I have to though._ ’ It was a promise he hoped to keep. ‘ _Also though, I don’t know where he keeps my boos, he separated me from them this time. Having him release them is faster and easier._ ’

E. Gadd fumbled and using a nearby machine pull himself up to his feet. He leaned on it as he pawed at his lab coat for a few seconds before pulling out an extra pair of glasses to carefully place on his face with shaking hands and a small wince. “Fine, I’ll… free your boos.” He grimaced, looking away, all his usual jovial energy completely absent. He was obeying though, which hopefully meant he’d make it out of this alive.

“And destroy all your machines meant for capturing and holding them?”

“Yes,” E. Gadd replied through gritted teeth, his knuckles whitening as he clenched his fist.

“Good! I suggest you hurry up before I get impatient.”

E. Gadd glowered at him but moved to do as ordered almost immediately. He was alive though and really that’s all that mattered, hopefully he was smart enough to keep it that way.


	3. Mario

Without the adrenaline coursing through him, the pain in Luigi’s arm was so much worse. It throbbed in time with the rather horrid headache that was rapidly setting in. He wanted nothing more than to lie down in a dark room and curl around his arm in wretched misery. But despite how bad it was, King Boo’s only complaint was that the blood leaking from it and soaking into his sleeve and getting all over his front too ruined the look he’d been going for.

‘ _It’s not my meat suit_ ,’ he explained. ‘ _So I have no reason to care if it gets damaged._ ’

Well _Luigi_ cared and he would very much prefer it not be. He had no say in that though. King Boo didn’t even seem inclined to bandage his arm because he was just like that.

Instead he focused on E. Gadd and ensuring he did as he was told and freed all the boos in the three vaults he’d kept them in. As soon as they were all released back into the wild, Luigi got an uncomfortably strong sense of King Boo’s happiness about it and this situation as a whole. He was almost tempted to cling to it to escape his escape his misery more but didn’t; he didn’t want to share in King Boo’s joy about any of this.

Next came the destruction of the equipment that had captured and held the boos, including the Poltergust E. Gadd had been seemingly been in the process of repairing before he tried to use it defend himself with it. King Boo stepped in to do that himself, using a mix of magic and Luigi’s fists and feet and eventually even a crow bar.

He was ruthless, zapping, punching, kicking, smashing, until E. Gadd’s machines were reduced to a pile of metal and wires. It made the pains Luigi was already experiencing worse and introduce new ones. And King Boo didn’t stop at the vaults and Poltergusts either, he started going to town on everything else in the lab too, his rage fueled by a personal vendetta.

E. Gadd tried to protest a few times but King Boo wasn’t listening, he gave up when King Boo threatened to kill him if he didn’t shut up. Polterpup stayed by him, always placing himself between him and King Boo growling ferociously whenever the latter moved too close. Overall, it was bad, stressful time for everyone except for King Boo.

“There, you’re done” E. Gadd said what felt like forever later when King Boo’s anger seemed to finally be spent and everything in the lab had been reduce to little more than piles of rubble. “Now release him.”

Panting a little from exertion, King Boo turned to face him with a grin, resting the crowbar against Luigi’s shoulder. “When did I say I was going to do that? I don’t think I even implied it as a possibility.”

E. Gadd gasped and glared. “But… you can’t… You got what you…”

“He’s my puppet, I’m not giving him up.” Lifting his chin, King Boo tossed the crow bar to the side and started for the exit. “Lucky for you though, I’ve decided to let you live. Leaving you alive after wrecking your lab, destroying your life’s work, unable to take revenge against me without hurting your friend even more than he’s already hurting is better vengeance anyway.” ‘ _If he attacks, I’ll change my mind though, I don’t like disrespect._ ’

Thankfully, E. Gadd just muttered a few more attempts at a protest that King Boo ignored completely. He followed King Boo out and to the car, only giving up when King Boo slammed the car door shut.

‘ _Let’s go pay Mario a visit now, huh?_ ’ King Boo said as he backed out of the driveway, running over E. Gadd’s mailbox in the process.

Just when things seemed they couldn’t get any worse too. … _Please don’t._ But… no amount of begging would convince King Boo to change his mind. He only took pleasure in it and thus… Luigi didn’t even try very hard. … King Boo laughed out loud about that.

By the time they reached Peach’s Castle, Luigi was tired enough that he probably would’ve been able to fall right asleep even with the pain in his arm. The bright sunlight as King Boo walked his body through the courtyard hurt his eyes and made him feel unwell – part of that might be blood loss though. Though it was nothing compared to the dread growing in him at the thought of Mario seeing him like this; a pitiful sorry state, actively violated by King Boo.

What was Mario going to do or think or say? Would he believe that this was Luigi’s fault somehow? How disgusted would he be? Would he even…

“Luigi?” It was a toad, he approached King Boo and Luigi hadn’t even noticed.

“I’m looking for Mario,” King Boo said, attempting to speak like Luigi.

“What’s up with the uh…” Toad trailed off, gesturing vaguely at his face. “And why are you dressed like that? And what happened to your arm? That’s not… blood is it? I don’t like blood.”

King Boo held back a sigh of annoyance. “I-I need to talk to Mario. It’s important. Do you know where he is?” His imitation wasn’t the worst in the world but with everything else it shouldn’t be at all convincing. … Unfortunately, the castle toads had never paid much attention to Luigi so this one looking like he believed it was not much of a surprise.

“Uh… uh… I’m not sure. Probably in the castle somewhere, maybe his room. You uh… should probably get that looked at if it is blood… it doesn’t look good.” At least it wasn’t actively bleeding anymore though, right?

“Yeah, sure, I’ll do that.” King Boo turned away to start for the castle again. ‘ _Toads are annoying, how do you put up with them?_ ’

Luigi should respond in defense of the toads but considering how that one had just mostly ignored the fact that something was _very_ blatantly wrong here he wasn’t even really sure he wanted to. And he lacked the energy to really try anyway.

As always, the door to the castle was unlocked. The toads guarding it reacted to Luigi’s current appearance much the same way the first one had, letting King Boo enter with little questioning. Ugh! How did they not see the crown and think ‘King Boo’? They’d never been the smartest folk around but surely they couldn’t be that stupid? … Then again though, other than the toads who’d come to the hotel with Peach, none of the castle toads had ever seen King Boo so maybe they just didn’t know.

‘ _Or maybe they just hate you. It wouldn’t surprise me._ ’ King Boo smirked as he strode freely into the castle.

_Maybe you should just shut up._

King Boo laughed internally. ‘ _Oh, getting angry now, huh? Sure did take a while._ ’

Luigi refused to respond. Everything he did or said only ever seemed to give King Boo cause to taunt him some more. So… he was just going to stop thinking for a while instead. … Too bad that was really hard to do.

The entrance hall seemed to be empty. So were many of the rooms and halls except for the occasional toad. Most were too busy to pay King Boo much mind but the ones that did, all believed his only half decent Luigi impersonation, expressing nothing but concern for his obviously sorry state. None of them knew where Mario was though, that was a relief.

Maybe Mario was out somewhere doing something with Peach or Yoshi or anyone else. Hopefully wherever he was, he’d stay there until something happened and King Boo was no longer a problem. … What were the chances of _that_ happening though? … King Boo’s response to that thought was a hearty laugh.

After searching half the castle, they ended up in the entrance hall again. Before King Boo could start for the other half, the sound of the entrance door opening drew his gaze. … It was Mario!

‘ _Finally!_ ’ King Boo was utterly delighted. Luigi was utterly the opposite.

Mario had spotted him too, pausing for a second before coming further in. “Luigi?” His brows were furrowed with worry as he came closer. “Toad told me you were looking for me. Are you… okay?”

No, Luigi was not okay. He’d never been less okay in his entire life. He desperately wanted to tell Mario that and... he desperately wanted Mario to save him.

King Boo laughed out loud, twisting Luigi’s face into an evil grin. “Hey Mario, it’s been a while. Though really, I don’t know how long it’s been, it’s hard to keep track of time while in captivity.”

Only a few feet away now, Mario stopped, his face hardening. “Who are you? And why do you look so much like my brother?”

“Can’t you guess based off the crown?” King Boo gestured to it. “And I look like your brother because in a way I am.”

_No, you’re not!_

Mario was silent for a few seconds before it seemed to click. “King Boo?”

“Yup!”

Mario rushed forward to grab Luigi by his shirt front. The look on his face said he wanted to punch King Boo and King Boo was going to let him. “What did do you do to him?”

“Nothing actually, well, other than steal his meat suit anyway.”

Mario's grip loosened as he stepped back, a look of horror coming over his face. “Is he… if you…”

“Nah, he’s still in here.” King Boo winked as he tapped the side of his head. “Which is the whole point of this. You can’t do anything to me without hurting your bro even more than you’re going to be hurting me. It’s brilliant, isn’t it? I should’ve thought of this a long time ago instead of trusting _Helen_ to do anything with her stupid hotel.” He did not like Helen, her obsession with him made him uncomfortable. … If only Luigi could do something with that knowledge or at least find it funny. “This is better vengeance anyway, don’t you think?”

Mario opened his mouth but failed to say anything for several seconds. “Why… just _why_?”

“Because I can and because I wanted to.”

Luigi willed Mario to run away now before King Boo could hurt him or _worse_. He’d have a better shot at fighting back than E. Gadd had but unable to fight back properly King Boo might still be able to…

_Please, you’ve had your fun, please just leave now. Don’t… don’t hurt him… please._ Luigi wasn’t even begging to be let go, he just didn’t want to watch and _feel_ as his hands were used to hurt the people he loved. He wouldn’t be able to take that, it was too much.

King Boo was _absolutely_ delighted with both the look of useless fury on Mario’s face and with Luigi’s desperate begging. He’d won, he was finally victorious over his enemies at last. No more would boos be sucked up into vacuums or bullied. He’d done what no other person had ever done before, he’d utterly defeated the Mario bros. And now he was going to have a little fun with that.

_No… please don’t_. Luigi pulled his mind away from King Boo’s thoughts as much as he could but they were too intense to get away from completely. _Please don’t hurt him._

King Boo took a single menacing step towards Mario and… Something hit the back Luigi’s head with a loud bang, bringing an intense flash of pain followed by blessed nothing.

***

Mario gaped as Luigi’s body crumbled to the floor in a heap. He’d seen Peach sneaking up on King Boo from behind but he hadn’t expected her to whack him with a _frying pan_.

“That’s my bro,” he said gesturing uselessly at his poor brother who’d already _clearly_ been through so much.

Peach nodded as she lowered the frying pan. “I know. But we needed to stop King Boo before he did something or before he left, bringing Luigi with him.” Yes, but surely there were less violent ways to do that. “So I knocked him out. Now all we have to do is take him to the doctor so she can look at his arm and uh… maybe head now too. And then we’ll lock him in a cell until we figure out how to get King Boo out of him.”

Mario could only groan. While that was a good plan and the only one they really had, it meant Luigi would most likely suffer even more. Why couldn’t there be a fix _now_?

“Come on,” Peach said as she put the pan away and crouched down to pull Luigi into a more upright position by his arms. “I need your help lifting him.”

Before obeying, Mario bent down to grab King Boo’s crown. It was much smaller now but still obvious. Maybe removing it would… Nope, it wouldn’t budge no matter how hard Mario pulled on it. So it did seem to be tied to his possession of Luigi’s body somehow but not in a way that made it any easier to fix.

“It’ll be okay,” Peach whispered as Mario gave up on that. “We’ll fix this, I promise.”

Feeling a bit choked up, Mario could only nod his thanks. Hopefully for Luigi’s sake, she was right.

While the castle doctor was patching up Luigi, Mario called E. Gadd. Surely if anyone knew how to fix this, it’d be him.

“Mario,” he almost shouted into the phone as soon as he picked it up. “Watch out for Luigi he’s…”

“Possessed by King Boo,” Mario interrupted. “You knew?” And didn’t think to call and share that news, really? It’s not like Luigi was his baby brother or anything, so why would he need to know something like that?

“Well uh… now that I think about, I should’ve called to tell you but uh… my lab’s in a bit of state.” He was too busy cleaning his lab to… “King Boo was rather thorough in destroying everything…” Oh. “… more than just the boo stuff too which wasn’t part the deal. Neither was freeing Luigi like I thought… hoped. He left me alive though so… there’s that. … I should’ve called.”

“What happened?”

“Well, Booigi came to my lab and tried to kill me. He would’ve succeeded if Polterpup hadn’t jumped him. Then he said he’d let me live, if I freed his boos and destroyed the boo vaults but he destroyed everything else too and I _watched_ because… there was nothing I could do and I thought maybe he’d let Luigi go after he got what he wanted but he didn’t and…” He made a wordless sound of frustration accompanied by the sound of his fist banging something metal.

With a sigh, Mario informed him on what was happening over here and the general plan which relied heavily on him. Everything in his lab being destroyed didn’t bode well for their plans though but it was still all they had.

E. Gadd hemmed and hawed for a few seconds after Mario finished talking. “Well, with my lab the way it is, I can’t guarantee anything but I’ll try. It might take a while though.” That… wasn’t surprising. Hopefully Luigi could hold on for a while longer.


	4. Victory

‘ _I forgot the living could turn off their consciousnesses for hours at a time._ ’

Luigi didn’t want to wake up and would’ve gladly sunk back into unconsciousness if he could. King Boo wasn’t letting him though; he wanted to wake the rest of the way up and he was the one in control.

‘ _It’s probably the one good thing about being alive, you get to take breaks from your mind._ ’

Fully awake now, Luigi’s head hurt in probably one of the worst headaches he’d had in his entire life. The light was too bright when King Boo opened his eyes and sitting up made him feel dizzy.

They were in a cell, one of a grand total of two in the basement of Peach’s castle. As far as cells went it was probably a nice one even if it was barren, it had even had proper bed, though it wasn’t comfortably by any means. King Boo frowned at all of it though, his experiences with E. Gadd’s boo vault and being trapped in a painting had instilled a very strong dislike of being locked up or confined in anyway.

‘ _It’s bigger though so I_ suppose _it’s not as bad. We can actually move around some, that’s new. I’d like to know how we got here though._ ’

 _We were knocked unconscious._ By something that had clearly hit them in the back of the head, judging based off the apex of the headache, and thus there was no way to know who or what had done it.

King Boo made a wordless sound of displeasure both internally and externally. ‘ _Stupid fragile meat suit._ ’ He might’ve complained more but before he could…

“Luigi?” Mario was at the cell bars, holding one as he peered in.

Luigi’s mouth twisted into another evil grin as King Boo slid off the bed. “Nope, a little whack on the head ain’t gonna get rid of me.” As he spoke, he strode confidently over to stand in front of Mario.

Mario grimaced but didn’t pull away from the bars. As long as they were there though, he should be safe. “Let my bro go.”

King Boo took great pleasure in saying, “No!”

“Do it or else.”

“Or else what? You’ll beat me up? Torture me? You’d really do that to your brother?”

Mario faltered. “What do you want? What will convince you to let him go?”

“Well, right now I want you to let me out of this cell.” King Boo could probably break out with a little bit of magic and possibly some force but he wanted Mario to be the one to let him out. “And the only thing that’ll convince me to let my puppet go is when I get tired of dealing with it.” ‘ _I’m still having fun though so don’t expect that any time soon._ ’ Great, perfect, just wonderful, Luigi’s suffering probably wasn’t anywhere close to being done yet.

“I’m not letting you out until you let him go.” … Did Mario have a plan? He had to, right? He was going to force King Boo out… somehow. Hopefully soon.

‘ _He can try but he won’t succeed._ ’ “I don’t think you understand the position he’s in. I’m in control of his body, he feels everything that’s done to it. So, if I were to say… let his meat suit starve to death, he’d feel it. Or what about this?” He pointed at Luigi’s arm, the one Polterpup had bitten. It hurt less now and was bandaged. He poked it, hard enough to awaken some of that pain. “If I rubbed dirt in this, how long do you think it would take for him to die of infection? I’ve heard it’s a pretty painful and slow way to go.”

“You…” Mario tried to interrupted but King Boo kept talking.

“I should be able to keep his body alive beyond what’s natural too, prolonging his suffering. How long do you think I’ll be able to keep that up? And how many of his bones do you think I can get away with breaking without hindering my own…”

 _STOP! No more, please!_ Hadn’t Luigi suffered enough already? He couldn’t bare the thought of going through any of that. _Don’t do that to me please! I can’t…. I just… can’t._

King Boo laughed out loud. “If only you could hear his thoughts. He’s begging me not to do that to him because he just can’t. And he’s oh so frightened of me, it’s wonderful.”

Mario glared with far more hate in his eyes than Luigi had ever seen before. “Don’t.”

King Boo stepped closer to the bars, grabbing one as he looked smugly down at Mario. “You going to try to stop me?”

Mario, always the brave one, didn’t back down or even flinch. “Yes. So, don’t worry bro, we’re going to save you. Just hold on, okay?”

Luigi wasn’t sure he could but if anyone could get him out of this, it was Mario. So… he’d try to, not that he could really do anything else anyway.

“You’re going to have to chain me up tight enough that I can’t hurt your brother’s body. And even then, if I struggle enough, I should be able to anyway. And what about my magic, huh? How are you going to stop me from using that to free myself or hurt him? _Also_ , if I absolutely must, I can stop his heart beating whenever I please and there’s _nothing_ you can do to prevent it.”

Now Mario did falter, his look of determination wavering, further pulling down Luigi’s own brief hopes of being saved. There… really wasn’t much or anything Mario could do stop King Boo, was there? Unless he had a way to exorcise King Boo this instant, there was no way he wasn’t going to suffer, potentially a lot, and maybe even die. Though, King Boo had already made it clear that that would be his last resort so by the time he did it, it’d probably be end up being a mercy.

“So,” King Boo, continued, reveling in his victory and forcing that feeling onto Luigi to increase his misery, “you’re going to unlock this cell door and let me leave unhindered.” Sealing King Boo’s victory once and for all. “Or I’m going to unbandage this,” he gestured to Luigi’s injured arm again, “and see how much worse I can make it with just my fingers. My suit’s already ruined, more blood on it won’t hurt.” ‘ _You think if I mess with it enough, I can get you to bleed to death from just this one wound?_ ’

 _Please don’t_. Luigi was already bracing himself for the worst though. In hindsight it made sense that King Boo could and would do such a thing if it could get him what he wanted.

‘ _I won’t, it’d be far too fast an end. And I like the infection idea more. I was just wondering because I actually don’t know that much about the living anymore, like how much blood you need to survive and stuff. Depending on what your brother does, I might get to learn some things though._ ’

Luigi never would’ve thought it possible but he was hoping Mario would do as King Boo said. As desperately as he wanted Mario to save him, he didn’t want to be tortured more than he wanted Mario to insist trying right now. He’d always been a coward like that. He wasn’t proud of it he couldn’t change it.

Mario glared at King Boo in silence, both hands gripping the bars now in a tight grasp. What he might be thinking, Luigi couldn’t guess but he could feel King Boo’s pleasure at the look of fury on his face. When he finally did speak it was through gritted teeth. “I hate you.”

“I know but you’re going to let me free anyway unless you’re okay with your brother suffering for a chance at defeating me. I’ll respect you if you are okay with that though, it’s certainly what I would do if I were somehow in your position.”

Those words seemed to break Mario. His shoulders sagged, the anger on his face melted to be more despair. “Fine,” he muttered under his breath after several seconds of defeated silence. He looked down and away for a second or two before looking back up to meet King Boo’s eyes again, with renewed determination. “Don’t think this means you win forever though. Luigi, I’m still going save you, okay? It’s just going to be a bit harder than I initially thought but I promise, I’ll do it as soon as possible.”

Luigi would’ve hugged him if he could and thanked him for acquiescing for now as well as for the promise. Mario had always been good at keeping his promises so honestly, he a had a bit more hope.

‘ _It’s foolish to believe he’ll save you,_ ’ King Boo said with a scoff. Luigi didn’t care what he had to say about it though.

Mario turned and left, presumably to get the keys. When he returned to unlock the cell, his determination remained as he glared at King Boo, unafraid.

King Boo grinned at him as he strode out of the cell. His evil glee in the moment was almost overwhelming as it washed over Luigi – ‘sharing’ a body with an evil person was horrendous in more ways than he ever would’ve predicted. His victory here was so utterly complete, he was he let free of his confinement by his captor, he barely even had to do anything. He couldn’t have asked for a better way to rub it in Luigi’s face or Mario’s.

To rub it in even further he stuck Luigi’s tongue out at Mario and lifted his hands to either side of his head, making L’s with them; the universal sign of calling someone a loser. It was so childish, it was almost funny in the context of how messed up this situation was and how evil King Boo was. … King Boo didn’t care about being childish though; he was the victor here so he could do whatever he pleased. He even half-skipped his way out of the dungeon area.

They didn’t encounter anyone else, not even a passing toad, on their way up and out the rear of the castle. That was probably for the best, Luigi didn’t want King Boo to be tempted to hurt anyone should they try to stop him.

Luigi’s car was still where King Boo had parked it, making it easy to circle round to it and find. _Where to now?_ Luigi asked with a mental sigh as King Boo hopped in.

‘ _Uh…_ ’ King Boo paused, holding Luigi’s hand on the ignition. ‘ _I don’t actually know. I didn’t think this idea would work so I didn’t plan for anything beyond this point. … You don’t have any more friends, do you?_ ’

 _Not really_. Unlike Mario, he’d always been bad at making friends.

‘ _Heh, pathetic. I guess we’ll just have to find something fun to do then._ ’ With a laugh, he started the car and drove away.

That was fine though. Luigi wasn’t being physically tortured and Mario had _promised_ to save him as soon as possible so. He just had to sit tight and be patient for now, everything would turn out okay in the end… hopefully.

**Notes for the Chapter:**

> There is going to be more to this story, I'm actively working on it. However it's more of a part 2 because the the goal/feel of the story is so different; when it comes out y'all will see what I mean by that. I'm either gonna upload it as a sequel or just keep it as one fic and clearly mark it as a part 2. I haven't decided which I'm going to do yet but if you have a preference feel free to tell me in the comments.
> 
> Also, just in general feel free to comment and tell me what you think of the fic/story so far. I had a lot of fun writing this and am having lots of fun writing part 2 as well so I'd like to know if people enjoyed it. No pressure though, I know commenting on fics and things can be really hard but if you can I'd really appreciate it.


	5. Bored

**Notes for the Chapter:**

> I decided to put them in the same fic mostly because they're in the same Word Doc so might as well. Now for the reason for this part 2 existing.
> 
> Originally I was going have the fic end on the open ended bad ending of King Boo winning but while I was writing the penultimate chapter of that I had an evil idea occur to me and felt called to do it so I did. (This next part is kinda spoilers for said evil idea which is revealed in fic at the very start of chapter 3, meaning 7 overall, this part 2 revolves around it so it's not a huge deal for it to be spoiled but if you want to find out what's up with what's happening when our characters do don't read the next paragraph.)
> 
> While writing the part where Luigi feels King Boo's emotions about his victory over the Mario bros in such a way that I wrote it as if I were writing from King Boo's POV, I had the thought of what if overtime because of this possession arrangement, their minds became closer and closer so that they started experiencing each other's thoughts and emotions in that way more and more until they essentially felt like or became the one entity instead of two? And then I was like, oh that's like fusion from Steven Universe but very much unwanted from both parties and very, very bad for poor Luigi because he's fusing with evil, violent King Boo. And then I had the idea for the scene that requires the new 'attempted murder that looks like attempt suicide' tag (happens next chapter, I'll probably put a thing at the top, saying how to skip it if you want) and that sealed the deal on me writing this.
> 
> I don't know if everything in it makes complete sense or if everyone's completely in character (especially E. Gadd, I never feel like I know what I'm doing when writing him but I do my best and that's all I can ask of myself) but it was a lot of fun to write regardless so I hope y'all enjoy it too. :)

‘ _I think I’m starting to get bored of this_ ,’ King Boo said as they woke up.

Groggy and hungover from last night’s drinking, it took Luigi a couple seconds to parse what King Boo had just implied. _Really?_ He didn’t dare hope… did he? He’d just about given up on this nightmare ever ending. The only solace he’d found was that King Boo liked to ‘escape proper consciousness’ as he liked to put it, meaning sleep, alcohol, and whatever drugs he could find to experiment with. It was highly unpleasant but at least Luigi was only partially aware of his situation for sometimes hours at a time.

‘ _Yep_.” King Boo sat up and looked around. They were on a rooftop, neither of them remembered how they’d gotten here. King Boo didn’t care though and Luigi was having trouble doing so either. ‘ _I think I experimented with about everything I can get my hands on. Also, you’ve stopped caring about stuff and that’s just plain boring._ ’ And as nice as this little vacation was, he really needed to get back to his boos soon, he was their king after all. … That wasn’t a thought Luigi was supposed to be privy to. ‘ _That’s another reason I want done with this._ ’ King Boo couldn’t be having Luigi knowing all his thoughts and feelings and the longer they shared a body, the more often that was occurring when he didn’t want it to. He couldn’t seem to do anything about it which was why this arrangement needed to end sooner rather than later.

He stood and walked them over the edge of the roof to look down at the street below. It wasn’t a super long fall but it would probably hurt quite a bit. King Boo was tempted to jump off to see just how bad it would be.

 _Please don’t._ Luigi would rather not take any more injuries than he already had. Even if lately King Boo possessing him seemed to make his body heal faster than normal, it still hurt. _You were thinking about letting me go?_

‘ _I didn’t say that, just that I’m getting bored of this. I need to decide if I should let you go or kill you._ ’ As far as Luigi could tell, he was honestly undecided. He could probably press at King Boo’s mind to find out why but didn’t dare. … If he did, that’d be weighing the odds against him.

_Uh… all righty then. I vote you let me go._

‘ _Killing you would be fun though._ ’

 _Not like this. You’ve already defeated me._ And Luigi was still ashamed of it. He should’ve been able to fight back but… it had just happened so fast. _Wouldn’t it be better if you… let me live to be tormented by that and… the fear that you’ll… come back and do it again?_ He understood King Boo far too well for his liking at this point. Being dead himself, he didn’t consider death to be a horrible fate.

He laughed out loud. ‘ _True. I could also turn you into a painting to crown this victory for ever._ ’ And if he ever wanted a meat suit to play around in again, he’d have it right there.

Luigi did the mental equivalent of a gulp. _You could do that too_. It’d be easier to rescue him from a painting though, right? … Theoretically yes, but King Boo wouldn’t let that happen. … It might be the best Luigi could hope for though.

Another laugh from King Boo, this one only Luigi could hear. ‘ _I guess it’s decided then, a painting it is_.’ He stepped back from the edge at last and started for the door that should lead into whatever building this was. Luigi groaned and pulled his mind in on itself as much as he could. Being turned into a painting was better than death though and probably better than his current circumstances so… maybe this wasn’t so bad?

**A few days later**

King Boo’s kingdom was unsurprisingly a haunted forest. One could tell at a glance it was haunted due to the tall spindly trees being dead and dark. There even seemed to be an almost visible murky atmosphere to the place before they’d even stepped foot into it. Which they had had to do because there weren’t any roads that led into it and certainly not enough space between the trees to allow for a car to pass through.

There didn’t even seem to be any path leading in. King Boo ditched Luigi’s car and strode right in, ducking underneath a low hanging branch.

The pace he set was steady but slow, he was in no hurry. Which was fine, it delayed how long it would be before Luigi ended up as a painting. … It was night though; the woods were spooky and dark, lit only by the partly clouded moon overhead and King Boo’s crown. And it was absolutely _crawling_ with phantoms, fleeting past Luigi’s peripheral vision and making all sorts of spooky noises just out of sight. If he had any control of his body, he’d have been shivering and jumping at every single sound, real or imagined and probably running the exact opposite direction

King Boo of course wasn’t bothered, he strode confidently through the dead underbrush and around the scary looking trees. ‘ _How are you still afraid of ghosts? You’ve defeated_ how many _with E. Gadd’s stinky vacuum?_ ’ He made a loud exaggerated gagging noise to emphasize exactly how the felt about said vacuum. ‘ _And we’re not even that scary to begin with_.’

Luigi didn’t get it either. It was illogical but they were still scary. He’d been working on that with Polterpup but then… this happened. King Boo scoffed and kept going.

Eventually they reached the clearing in which King Boo’s mansion took up majority of the available space. It was old and scary looking but not as large as Luigi would’ve thought it would be. Which didn’t mean it was small by any means but definitely not as big as Peach’s castle.

As they approached the entrance, three boos came shooting out, phasing through the door. Internally Luigi jumped and screamed, the only thing worse than ghost creeping through the shadows was ghosts popping out at him. … King Boo found that was funny, he should’ve tried jump scaring Luigi more, maybe one of his past schemes would’ve been successful if he had.

The boos looped around, slowing to a rest in front of King Boo and Luigi. “Welcome back boss,” the boo on the left said.

“You still have Luigi,” the middle added.

“What are you going to do with him?” the right boo finished.

King Boo gave them a genuine smile, not his typical evil one but one that felt as if he was just happy to see his boos again. Which was _such_ a strange feeling from him, it was actually creepy.

“I’ve decided to turn him into a painting,” King Boo said, pushing down his annoyance that Luigi was more privy to his thoughts and feelings than he was supposed to be.

The boos laughed in near unnerving unison that sent a shiver down Luigi’s metaphorical spine. They followed King Boo back in as he entered.

Inside was a surprisingly grand living room. A large cushy sofa with matching chairs and cushions took up the bulk of the floorspace on top of a thick rug covered in intricate designs. A gorgeous crystal chandelier huge down from the ceiling, the dancing light from the fireplace, reflecting off its dangling bits, giving it an almost sparkly look. There was a large painting of an abstract night sky hung above the fireplace, completing the fancy feel of the room. If it wasn’t for the many boos and even a few standard ghosts suddenly all turning to look at him, Luigi probably would’ve found the place quite nice.

Abandoning their comfy seats, all the boos and ghosts rushed to crowd around King Boo. Being surround by a horde of boos was perhaps the scariest thing Luigi had encountered in a while. … All they did though was welcome King Boo home and congratulate him on his victory over the Mario bros. They all seemed happy to have their ‘boss’ back and King Boo was glad to be back.

‘ _See? Not so scary._ ’ Well… Luigi still didn’t like it no matter how ridiculous King Boo thought he was being.

Once all the ghosts had finally had their say, King Boo ordered them to take down the night sky portrait and put it in the music room. He then ordered another boo to bring down an empty painting frame that would take its place. It was rather obvious what that empty painting frame was for.

How aware would Luigi be in the painting? Mario and the toads had all said they didn’t remember anything of it so maybe it’d just be like a long sleep. Which honestly wouldn’t be so bad even if it lasted for forever. But… what if one was aware while in a painting but didn’t remember anything of it when they came out? Did that even make sense?

‘ _When_ I _was trapped in that painting you and E. Gadd put me in, I was aware of every moment of it,_ ’ King Boo cut in with an inward snarl. ‘ _So I_ really _hope you will be to._ ’

Luigi whimpered but did his best not to think about it anymore. … Except the boo ordered to retrieve the empty painting frame choose that moment to swoop back into the room and present it to King Boo, holding it ready for him.

‘ _Anything else you want to say to me? Beg for mercy perhaps?_ ’ King Boo hoped he would, it’d be a great send off. If Luigi was convincing enough, he might even…

 _No!_ Luigi could feel the lie in that thought. He wasn’t going to get mercy no matter how much he begged so he _wasn’t_ going to. _Just get it over with already._ It’d be better than having his body controlled by King Boo for even a second longer.

King Boo chuckled. ‘ _Finally, some backbone. Very well though, this was fun. Maybe I’ll pull you out occasionally to play around some more. For now though, goodbye._ ’

He called on his power, causing his crown to glow brighter. There was an uncomfortable pulling sensation on Luigi’s soul and… King Boo’s magic sparked and fizzled out. … They were suddenly both very worried and Luigi couldn’t tell where his concern ended and King Boo’s began. … King Boo pushed that aside though and tried again, putting more force behind it. … It still didn’t work, the same thing happened as before, only more intense.

Growing desperate now, King Boo tried again. This time he kept pulling past the point of discomfort until… it felt kind of like their souls were struck by lightning as his magic sparked again, sending a tremor through both of them that translated into a physical shudder.

“What’s wrong boss?” the boo holding the empty painting asked as they all crowded a bit closer.

King Boo looked up at him, his hands trembling a little as he forced an unsteady smile. “I think I might be stuck in here.”


	6. Stuck

**Notes for the Chapter:**

> This is where that 'attempted murder that looks like attempted suicide' tag comes in. It's pretty graphic, definitely the most graphic thing I've written in years, so if you'd prefer not to read it, read up until King Boo says 'Actually, maybe I don’t need a painting of you after all.’ and then skip to the 'Two weeks later' break.

_We should go to E. Gadd._ Luigi finally suggested.

‘ _No, absolutely not!_ ’ King Boo would rather do almost anything else.

_Even stay stuck like this?_ It had been well over an hour since they’d found out about their predicament and all King Boo had done was pace around in his bedroom – if it could be called that when it didn’t have an actual bed – and occasionally try to free himself from Luigi’s body. Failing every time and causing nothing but pain and discomfort for both of them.

‘ _I’ll figure something out._ ’ What though? He’d never possessed a living being before. He hadn’t known it was possible to get _stuck_ in them, if he had he probably wouldn’t have attempted it. … Luigi would’ve far preferred that.

_What else can you_ try _? E. Gadd’s an expert on ghost stuff, I’m sure he can find a way to fix it._ And if that’s how the problem got solved then Luigi would be… No, he shouldn’t think about it because then King Boo would know the thought too. … It was too late though, wasn’t it?

‘ _Yep. I’m not giving you up yet. I’ll find a way to fix this and then… Actually, maybe I don’t need a painting of you after all._ ’ Even before completing the thought, King Boo reached into his suit pocket to pull out a butterfly knife he’d stolen from someone the other day because he’d wanted to ‘play with it’. The most surefire way to free a soul from a living body was to kill the body.

He flipped it open and… Out of sheer desperation and fear Luigi somehow managed to stop it a few inches away from his neck. That was _all_ he could do though. His hand shook as he held it there, pointed at his throat, straining against King Boo’s control.

King Boo growled out loud and internally. Luigi was leeching off _his_ magic to fight his will; how _dare_ he? … Luigi had no idea how he was doing it, nor did he really care right now, he was much more concerned with _not dying_.

‘ _You’re going to die whether you like it_ not _!_ ’ King Boo started pushing harder, pushing his will against Luigi’s.

Luigi managed to hold it there for several seconds but… King Boo was strong and determined and…

‘ _You’re_ pathetic _! You know you can’t win so stop trying!_ ’ It was King Boo’s voice but it was the kind of thing his anxiety would say to him because well, it was true. There was no way he could win this battle when it took everything, he had to just hold the knife still.

He whimpered internally as the knife inched closer. King Boo’s rage at Luigi being able to fight him even this much and leeching off his magic to do it radiated from him in a way that felt almost physical, heightening Luigi’s fear and distress. … Maybe if Luigi could move his other hand over to help push the knife down… Nope, trying just gave King Boo more leverage to overpower him.

His will broke as soon as the knife touched his flesh; he’d never been very strong. Hot blood gushed around his hand as King Boo pressed the knife in as deep as it would go, going for the jugular because even he knew that was a weak point for the living.

It _hurt_ unbearably so but not with the all-consuming pain he’d have imagined a fatal blow to be. It quickly grew so much _worse_ though as King Boo started dragging it across his neck. It was sharp but apparently not sharp enough; it met a fair bit of resistance that King Boo had to force it through before reaching the other side and _finally_ pulling it out.

‘ _That should do it._ ’ Even in his own head, King Boo’s voice sounded distant behind the pain and the blood gushing from his throat as he struggled to breath. His body barely even reacted though; King Boo was in control and he wasn’t going whine about a little bit of pain even if it was bad enough now to make him uncomfortable too.

Blessed blackness ate at Luigi’s vision. He welcomed it but… King Boo didn’t. Pulling on his magic enough to make crown glow brighter, he pushed it away because… he wanted Luigi to suffer for fighting him and leeching off his magic and because being stuck in his body for any length of time was rage inducing. … Luigi could only whimper at that and at the sight of his front as King Boo looked down. There was an awful lot of blood soaking into the once white suit, some of it leaked down his throat too; hot and uncomfortable, drowning him.

_Please… please… just… make it stop… please._

‘ _No. I’m going to tell Mario about this next time I see him. I want a good story to share since I won’t have my painting._ ’ And he was curious about how long it would take for Luigi to die and what it would feel like for him when it happened.

That was even worse. _Please…_ No amount of begging would get him anywhere though so with the last bit of willpower he had left, he made himself stop; he didn’t want to give King Boo any more satisfaction.

The next… however long was absolute torture. Effected by the body’s weakness as blood poured out of it, King Boo did soon end up lying down on the couch.

All Luigi could do was moan and whimper internally as overtime his entire body grew numb and cold, adding to his discomfort and misery. It wasn’t dignified, he’d rather go out in stubborn defiant silence but that was far too much to ask from himself. Instead he found what small comfort he could in the fact that it annoyed King Boo.

But despite how annoying he found it, King Boo didn’t complain as his rage faded over time. He didn’t even say anything; he could let Luigi have his misery while he was dying. It was a shame but nothing else could be done, better him dead than King Boo trapped forever in his meat suit.

Except… death never came for him. What had to have been hours passed and yet Luigi was still alive and King Boo was still trapped in his body. He even actively tried to escape again, several times, all to no avail. Even using his magic to manually repress Luigi’s erratic off rhythm heartbeat did nothing, it just restarted as soon as he let go of that magic.

‘ _You don’t seem to be dying,_ ’ King Boo finally broke the silence. ‘ _I’m not even sure you’re losing blood anymore._ ’ A _lot_ of blood had soaked into his clothing and the couch beneath him, filling the air with an unpleasant coppery smell. How was it possible for someone to lose that much blood and still be alive, let alone conscious? He wasn’t even really _breathing_ anymore, how was he still alive?

Unable to form a coherent proper reply, Luigi whimpered again. He still _felt_ like he was dying but didn’t seem to be. Why? Probably something to do with King Boo possessing him, right?

‘ _Yeah, probably. It’s not something I have control of though because I would really prefer you die already._ ’

Luigi wasn’t in total disagreement. He wanted this torment be _over_ , if that meant death then so be it. But as in all things in his life now, he didn’t have a say in it.

King Bow scowled. ‘ _We’ll have to figure something else out then._ ’

**Two weeks later**

From the car, King Boo glared at E. Gadd’s lab. He _really_ didn’t want to go to him of all people for help but he was the only ghost expert either of them knew of. King Boo had _tried_ to find another one but failed at every turn. He’d even tried killing Luigi a few more ways, none succeeding.

_Just go in already._ Luigi was tired and frustrated and just wanted this to be over with. He wasn’t even sure if any of the anger he felt was truly his own or if it all came from King Boo. It seemed to get harder to fully separate their emotions with each passing day. It was scary and made them both increasingly desperate to be free of each other.

‘ _We could try jumping into a pool of lava._ ’ … What if that destroyed him too though? It would certainly destroy his crown; it helped him channel and even amplified his power a little so he’d prefer not to surrender it unless he absolutely had to. So… E. Gadd it was. His anger about that warred with Luigi’s hope for rescue.

With a disgusted half growl half gag, King Boo exited the car at last. Scowling, he slammed the door shut before starting up the driveway, crossing his arms.

_Can I…_

‘ _Yeah, fine, whatever, you can talk to him. I don’t fucking care._ ’ And he’d rather _not_ ask one of his arch nemeses for help anyway.

Luigi wanted to be fully happy about that but King Boo’s grumpiness made it hard. On the bright side though, said grumpiness was dampened by _his_ feelings. King Boo wasn’t completely in control of this situation anymore.

He rang the doorbell this time. When no one answered after several seconds, King Boo pressed it again. Still nothing though so… King Boo started spamming it. If E. Gadd didn’t answer the door soon, he was going to…

Loud barking came from the other side followed by E. Gadd’s muffled voice shouting, “I’m coming, I’m coming, hold on a sec.”

King Boo would’ve kept ringing the bell out of spite but Luigi asserted a bit of his will and made him stop, pulling his had back to clinch in a fist at his side. Whatever was going on between them allowed Luigi to access some of King Boo’s magic as he’d discovered two weeks earlier and it had only gotten easier to do since then. Which of course made King Boo mad but there was nothing he do about it so he could suck it up.

‘ _My will’s stronger though. So if it came to a fight for control, I’d win every time._ ’

Luigi wasn’t sure about that. King Boo wasn’t fully sure of that either though; he was just trying to be intimidating. It would’ve worked a few weeks ago but not anymore, not when Luigi’s normally fragile confidence was bolstered by King Boo’s tendency to be overconfident.

Before King Boo could try to regain some intimidation, the door opened at last. E. Gadd gasped and flinched at the sight of them, before his expression settled into an angry glare. Polterpup stood at his feet, growling.

“You’re back,” E. Gadd said. His face was still a little bruised, considering how long it had to have been, that had to mean it was really bad before. “What do you want this time?”

“I-I’m so sorry professor,” Luigi said, instinctively taking control even as King Boo let him. His voice was a bit rough and it hurt to speak, the wound on his throat was rapidly healing but it was still there. He didn’t care right now though, he needed to apologize.

E. Gadd’s brows’ rose as Polterpup’s growling faltered. “Luigi?”

Luigi nodded as he grasped the doorframe, sagging into it. E. Gadd jumped up and babbled incoherently for a second or two before rushing inside, gesturing for Luigi to follow.

Inside, the monitoring room was still a mess, it was least essential though so of course it would be fixed last. Luigi didn’t have time to follow E. Gadd into the lab proper to see how it was though before E. Gadd was rushing back out of it with a chair.

“Have a seat sonny, you look worn out,” E. Gadd said, particularly vibrating with excitement.

Fighting the strong desire to stay standing that came from King Boo, Luigi sat, sinking into it. He almost felt like he might tear up with exhausted relief; this was the first time he’d been in full control of his body since King Boo had initially possessed him. … If he _did_ start crying King Boo was going to take that control away though because as long as they were stuck in the same vessel together, there would be no physical tears, they were gross.

“How did you do it?” E. Gadd asked. “How did you banish King Boo from your body?” He clarified when Luigi gave him a blank stare.

“Uh… I didn’t.”

“Oh! You wrested control from him then! I didn’t think you had it in you to best him, good job.”

“Uh… I didn’t really do that either.” ‘ _And couldn’t if you tried._ ’ _Hush!_ “It’s more uh… he doesn’t want to talk to you so he’s letting me. I… uh… _we_ need your help. He’s kind of stuck in my body and wants out but can’t get out on his own so… here we are.” Should he say anything about whatever their thoughts and emotions were doing? … No, no one needed to know about that unless absolutely necessary. … And Luigi didn’t want to talk about the whole attempted murder, resulting in finding out he apparently couldn’t die now thing either so that was all he was gonna mention for now.

E. Gadd’s excitement died down for a few seconds before his borderline evil scientist grin returned. “Really? I don’t think I’ve ever heard such a phenomenon. To be fair though, I don’t think many ghosts or boos possess the living, especially for so _long_. We’ll have to look into it. Come along!” He hopped back and dashed back towards the lab proper, clearly expecting Luigi to get up and follow him.

With a tired sigh, Luigi looked down at Polterpup who was staring up at him. “Puppy?” he said, reaching a hand out towards him in an offer for pets. Polterpup snuck closer and sniffed at it hesitantly. He apparently didn’t like whatever he smelled thought as he growled softly and backed up again. … He smelled like boos and King Boo specifically, what more did he expect? … Probably a fair point, especially considering their last interaction.

“Get in here!” E. Gadd said as he poked his head back into the room.

Holding back a groan, Luigi forced himself up and into the lab.

It was still a mess. Luigi flinched at the sight of it, trying not to feel King Boo’s pride over it. It was obviously on its way to being cleaned up and fixed but… it would take a while, most of everything was still little more than rubble.

_It being such a wreck will probably make it harder for him to help us._ … Oh, King Boo hadn’t considered that. That would’ve been a valid reason not to come and continue to seek other solutions. … It was too late now though. … If he couldn’t help them, King Boo would kill him after all.

_No, absolutely not!_ Luigi wouldn’t allow it. … That battle for control might become a thing after all then.

_And I’ll win._ They thought at each other in perfect unison; it didn’t even feel like separate thoughts but one shared thought. … Neither of them liked it and would rather never do it again.

‘ _Stop thinking and feeling the same things am I._ ’ King Boo growled internally. ‘ _I want you_ out _of my head._ ’ Luigi couldn’t agree with that sentiment more with the added bonus of wanting King Boo out of his _body_.

A loud snap right in their face pulled them both back towards the outside world.

“Look alive sonny, we got tests to run,” E. Gadd said, stepping back. “Lucky for you, one of the first things I fixed is the scanner equipment. I was modified it to keep track of where you were. I lost you for while but then but you came right back to my door. With a few more tweaks to it, I might be able to figure out what’s up with King Boo being stuck in your body.” And knowing that, hopefully be able to fix it. If he couldn’t then… that wasn’t something either of them had any desire to consider.


	7. The Problem

It took more than an hour of tweaking and adjusting the scanner for E. Gadd to finally declare a verdict. “Your souls are merging,” he said, looking up from the scanner’s readout on his laptop.

“Uh… what does that mean?” Luigi wasn’t sure he wanted to know. Neither he nor King Boo liked the sound of it though.

“It means, your two separate souls are starting to merge and eventually will become _one_ soul.” E. Gadd demonstrated with his index fingers as he spoke, holding them apart and bringing them together at the end. “You’re essentially on your way to becoming a single consciousness instead of two separate ones.”

“What… that…” Luigi stammered before being cut off by King Boo. “You better just be trying to scare us old man.”

Despite their last interaction and the way King Boo glared at him, E. Gadd now seemed unphased, confident that their need for his help kept him safe. “Why would I lie about this? It’s fascinating, I’ve seen anything like it.” He paused to look off to the side in thought, even raising a finger to his chin. “I wonder what could be causing it. Without more data and info, I can’t say for sure, but I believe it must have something to do with how long your souls have been in the same body together. There could easily be other factors in play in as well. It’s something I loved to look into further but…” He trailed off with a grimace as the tilt of his head indicated he was looking at Luigi and King Boo again.

King Boo and Luigi were in total agreement that the how and why of it didn’t matter, what mattered was… “Can you fix it?” The somehow managed to both speak at once. Which, now knowing _why_ they were syncing up, made them even more displeased about it than before

“I don’t know yet. However…” E. Gadd snapped his chair around to face his desk, the remnants of the computers once there long since moved away and replaced with disorganized papers and various kinds of junk. He moved his laptop to side of it to begin sorting through the papers. He quickly found whatever he was looking for and hopped up out of his chair to rush over to stand next to Luigi.

“Behold the KBE,” he said, holding it out so they could both see it. It was a set of blueprints depicting a seemingly hollow machine. His chicken scratch handwriting all over it was borderline illegible. “That’s short of ‘King Boo Exorcist’.” King Boo snarled inwardly at that name but didn’t say anything for now because E. Gadd was still explaining. “It’s designed to force King Boo out of your body and hopefully leave you soul intact during the process. I’ll have to modify its design and change some of its innerworkings now that we know your souls are merging. But since I haven’t even started building it yet, thanks to a certain _somebody_ wrecking my lab, forcing me start from the ground up, that shouldn’t be too difficult. … Hmm… I might need a few more parts though, I don’t know yet.”

“Uh… I’ll help if you need me too,” Luigi said with only a little reluctance from King Boo. The sooner this was dealt with, the better, especially since there was probably a point where it would no longer be reversible. … Hopefully they hadn’t already reached it or were anywhere close.

“I don’t think you or King Boo could help with building or designing it, you’d probably just get in the way if you tried. For the heavy lifting stuff and finding the needed parts, I already got a couple helpers, they should be back soon too now that I think about it. But if it’s needed, one more helper can’t hurt. Or uh… I guess it’s actually two helpers, huh? Hmmm… I never would’ve thought I’d have a chance to have King Boo himself as a lab assistant. Just think off the experiments I could run. I could learn so much about him and boos in general if he were a willing participant.” He grinned, rubbing his hands together in glee as he placed himself back on his computer chair.

King Boo bristled and made a hissing sound. “I didn’t volunteer to help you. _You’re_ helping me with my problem because I’ll kill you if you don’t, understood?”

That gave E. Gadd pause, his glee fading. “If I fail though, your soul and Luigi’s will fully merge. Not something I’d like to let happen, even if I do stand to learn a lot from witnessing and studying it as it does. But in the event that I fail and that _does_ happen, I predict his kindness will dampen your blood lust enough that you won’t kill me.”

King Boo growled. It wasn’t long ago that he’d had E. Gadd’s life in his hands, maybe it was time to remind him of that. He took a step forward, lifting a hand to grab him by the neck again.

_No!_ Unlike Luigi’s previous attempts to stop King Boo from doing something, this worked. He didn’t take back full control of his body but just enough to cause King Boo’s next attempt at a step to end with them falling face first onto the floor instead.

“Oh,” E. Gadd said from above them. “You okay sonny?”

Luigi hadn’t been okay for what felt like forever now, he barely even remembered what ‘okay’ felt like. So he didn’t even try to respond as King Boo stood back up to brush himself off with an annoyed huff. He _hated_ that Luigi could do that now, he _wasn’t_ supposed to. … Too bad, Luigi could and because of that, he wasn’t going to let King Boo hurt anyone ever again, _including_ _me_. Luigi needed to make that very clear because he was _never_ going to go through _that_ again. If King Boo didn’t like it – which he didn’t – he’d just have to suck it up and deal with it because Luigi was _done_ with his bullshit.

‘ _I hate you._ ’ … The feeling was mutual; Luigi had never hated anyone more. … But as much as King Boo hated the reminder of Luigi’s growing ability to fight him, it made it pretty clear that he wasn’t in full control of the meatsuit anymore. Which unfortunately meant to make getting free of it easier and faster he might have to do the unthinkable and actually endeavor to get along with his enemy lest they merge or whatever. And honestly, Luigi leeching off his magic was just _the worst_ and unacceptable, so much so, he might be willing to avoid giving him cause to do so when possible.

Luigi had to do the mental equivalent of a double take. If his mind wasn’t running so closely to King Boo’s he never would’ve believed it. _Are you really thinking we should get along for now?_

King Boo _hated_ that Luigi could read his inner thoughts so clearly. There was nothing he could keep hidden anymore when he was supposed to be the one in control and the only one doing the mind reading but… ‘ _Yes, that’s what I’m thinking._ ’ He didn’t want Luigi fighting him for control every step of the way. ‘ _We both want the exact same thing._ ’ And honestly King Boo wanted it so bad he’d be willing to let Luigi go free if that’s what it took. ‘ _So for now, it’ll be easier for both of us if we cooperate._ ’ It grated for him to admit it but their souls fully merging would be _far_ worse than losing a little bit dignity.

Luigi loathed the thought of getting along with King Boo but… he was right. It’d be easier for both of them to avoid fighting if they could. And… they’d both do whatever it took to increase the odds of becoming free of each other.

It made sense but… _I can’t believe you’re the one who thought of it._

‘ _I can be reasonable sometimes._ ’ He was going to say more but…

E. Gadd grabbed Luigi by the tie and pulled him down to eye level. “Is you staring off into space like that going to become a thing now? What’s going on in that head of yours?” He poked the side of Luigi’s head.

Neither of them liked this invasion of space, King Boo far more so, but as promised, he let Luigi gently pull away. He was the one who spoke though. “Just coming to an agreement not to kill or threaten to kill you for now. You _better_ fix this though.”

E. Gadd nodded. “I intend to. The pursuit of science is important but Luigi deserves better than to have his soul wrapped up in _yours_ for forever.” There was an uncharacteristic amount of venom in his voice. It sounded weird coming from him but was heartening to hear.

**An hour later**

While E. Gadd went over the KBE blueprint Luigi and King Boo kind of just hung out in the lab. He called them over for more tests and scans twice but in the meantime, they found a spare chair to sit on while Luigi worked on regaining Polterpup’s trust. Though really it was more King Boo’s convincing Polterpup that all was fine with him now. He was more of a cat person but dogs were cool too, even ones that were traitors.

But alas, very soon after they had him playing fetch with them, he lifted his head to look towards the exit. A half second later, he jumped off and ran out into the front room. Good things never lasted long, did they?

The doorbell rang. E. Gadd, froze and looked up, hopping off his chair. He got halfway to the door before he paused to look at King Boo and Luigi. “Oh uh… I probably should’ve told you who my current lab assistants are, huh? Whoops. Oh well, too late now, you’re about to find out anyway.” With a wave of his hand to follow, he resumed exiting the room.

With shared curiosity, King Boo stood up and followed. They arrived in the front room in time to watch Gooigi enter, helping someone still outside maneuver a stack of boxes on trolley inside.

“This,” E. Gadd said as King Boo stepped up next to him, “is most of, if not all of what I need to make the KBE. With my lab all busted, I had to order in special parts from all over and have them custom built elsewhere. It was expensive but Princess Peach actually funded all of it because…” He continued but Luigi was no longer paying attention because E. Gadd’s other assistant and the one helping bring the boxes in was…

“Mario!” Luigi stepped forward, intending to rush over and hug him. It had been far too long since he’d seen Mario, he’d missed him _so_ … His second step failed as his leg refused to move, resulting in him stumbling and landing on his face again.

Evil bastard that he was, King Boo laughed. ‘ _Vengeance for earlier._ ’

_Me trying to hug my brother and you trying to choke E. Gadd are not comparable._ And King Boo had promised to get along. The idea to do so had even come from him.

‘ _Yeah, yeah, yeah, I know. I’ve had my fun, I’ll be good now._ ’ Mostly anyway. He even stood them back up.

Mario had approached but hung back nervously. He opened his mouth to say something but before he could, Luigi hugged him. He froze for a second before hugging back. “Luigi!”

Luigi did his best to ignore and push back King Boo’s distaste for this, drown it out with his own intense feelings. He even succeeded a little.

‘ _Stop it! It’s gross! I don’t want to feel that!_ ’ King Boo fought but leeching off his power, Luigi managed to maintain control for now. He’d been having an _awful_ time these past few weeks especially and he’d been so lonely and afraid and missed his bro so much, he was going to enjoy this brotherly hug for as long as he possibly could and there wasn’t a _single_ thing King Boo could do stop him.

“It’s okay,” Mario said, lightly patting his back.

Oh! Luigi wasn’t sure when he’d started but he was crying as he clung to Mario, more sobbing really. He wanted to explain; tell Mario how horrible and awful his life had been lately and how scared he was by this new revelation, and how much he _didn’t_ want his soul to merge with King Boo’s, but he lacked the words so… he just clung on him for dear life and cried instead.

“We’re okay now.” Mario sounded very unsure of his words but it didn’t matter. All that mattered right now was that he was here.

Eventually his tears petered out, leaving him feeling drained and exhausted but overall better. And… horrified and disgusted, that he’d cried at all, especially so much… no, that feeling came from King Boo. He still didn’t want to let go yet but… King Boo made him.

Mario gave him a small hopeful smile, keeping a welcome hand on his arm. “This means King Boo’s gone or uh…” his eyes shifted up towards King Boo’s crown for a brief second before meeting Luigi’s again, “something, right?” He looked so hopeful, Luigi wanted to lie and…

“Nope, I’m still here,” King Boo said, making Mario flinch away, breaking contact completely. “And very unhappy with everything that just happened.” He was even a little frightened by how overcome with Luigi’s emotions he’d been. Even now, he couldn’t muster up nearly as much hate for Mario as he knew he was supposed to have. … Good!

“S-sorry,” Luigi said, pulling his arms in to hug himself. Maybe… he shouldn’t have hugged Mario when Mario didn’t know King Boo would technically be part of the hug too but… he’d just needed it so bad. “I… we’re… he’s kind of stuck in me and….

“Our souls are merging,” King Boo cut in because he wanted to see the horror on Mario’s at the revelation. He wasn’t disappointed either. “Meaning if we don’t fix it, and get me the fuck out of this meatsuit, we’ll cease to exist as separate entities. Which I’m sure you can guess is something neither of us want and so here we are, trying to get it fixed before it’s too late.”

“Mamma mia,” he muttered under his breath; his way of not cursing. King Boo hated it.

“He’s uh… playing nice for now,” Luigi said. “Mostly anyway.”

“That uh… good. Can E. Gadd can fix the whole…” Mario gesture vaguely towards them, “… soul merging thing?”

“Hopefully,” they said together, hating that they’d done so even as they did it. But having exhausted all other options already, E. Gadd was their only remaining hope.


	8. Discussion

Back in the lab, the boxes were placed haphazardly all over the floor. E. Gadd was already sorting through them while Polterpup chewed on a bone in the corner and Gooigi seemed to just be sort of standing around, watching. They looked up and lifted a hand in a small wave as Luigi, King Boo, and Mario entered. King Boo even let Luigi return with his own wave. It was nice to see Gooigi again, though Luigi felt a bit bad about having not thought of them much the past however long King Boo had been possessing him for.

“Did you tell him?” E. Gadd asked, looking up from his work to swivel around in his chair to face them. It didn’t take a genius to figure out what he had to mean.

“Yes,” Luigi said. He would’ve still preferred not to but there was no way they could’ve kept it a secret for long no matter what.

“Good. I already explained to Gooigi so you don’t have to worry them.” That was one worry off Luigi’s plate at least. Whatever Gooigi felt about the situation was impossible to guess but that was how it was always was with them.

“You can fix it, right?” Mario asked, walking around the boxes to stand by E. Gadd at his desk.

“I don’t know yet but I’m going to try. I have to adjust the KBE blueprints some and might need to send you four out for more parts to build it. So it’s still days if not _weeks_ away from being done. And I don’t even know if that time frame’s going to be an issue or not. How fast does it take for two souls to become one? At what point does separating them become impossible? There’s so much we don’t know.”

Neither King Boo or Luigi had thought to consider that before. What if they’d already reached the point of no return? If not how far away were they from it? It could potentially take _weeks_ for E. Gadd to finish the KBE, that was a scary amount of time when under an unknown time limit.

“You two,” E. Gadd said, pointing at King Boo and Luigi, “You haven’t said anything about it but you must’ve noticed symptoms of what’s happening with your souls by now. About how long ago did they start? If we can pinpoint about when the process began, we might be able to calculate approximately how fast it’s occurring.”

Both of them thought back to when they’d first started becoming more aware of the other’s thoughts and emotions. They both came up blank though; their memories from before their trip to the Boo Kingdom were foggy and indistinct. Neither of them were even sure how long King Boo had been possessing Luigi for.

_Which is your fault_. If King Boo hadn’t been running around injecting Luigi’s body with every chemical he could find they would know more. _Also,_ he would’ve gotten bored of the game sooner, possibly resulting in them not being in the mess in the first place. Or heck, if he just hadn’t possessed Luigi in the first place, things would be better for both of them.

‘ _How was I supposed to know this could happen? If anything, it’s your fault for making defeating you any other way so difficult._ ’

In the interest of keeping what little peace they could have Luigi wasn’t going to reply to that. “Longer than two weeks ago,” he said out loud instead.

“Much longer?” E. Gadd asked. “Or about two weeks?”

“Uh… I…” Luigi began before King Boo cut him off. “We’re not entirely sure because most of our time was spent experimenting with every inebriating substance we could get out hands on. As a result, we were barely aware of much of anything a lot of the time, let alone our thoughts getting closer, and we certainly can’t remember any of it well. So we can’t say when it started, only that it was longer than two weeks, probably by a fair bit. Before we found out about it was fun though, drugs, alcohol, and the ability to sleep are the only good things the living have.”

_Why’d you have to tell them that?_ Luigi had had no control for any of it but he still felt ashamed and would’ve preferred no one ever knew of it. … Which was _exactly_ why King Boo had told them.

Mario glared but as he opened his mouth to speak, King Boo cut him off.

“Before you get all mad at me about that, let me share just one more thing and ask a very important question related to it.” With an evil smile, he pushed back against Luigi’s attempt to make him shut up because mentioning _that_ wasn’t necessary. Luigi didn’t want to think about it ever again. … Too bad, King Boo wanted to know why it had happened and there was a chance it might be useful information to E. Gadd. “On the day we discovered our predicament, I tried multiple ways to fix it myself. I only came here as a last resort after all. But the way that definitely should’ve worked but didn’t for some inexplicable reason was death. I tried to kill the meat suit but it wouldn’t die.”

“You did _what_?” Now Mario was _really_ mad as he took a menacing few steps closer.

With an evil chuckle, King Boo pulled down the collar of suit, better revealing the mostly healed wound on Luigi’s neck. “I slashed his throat,” he said as he ran the thumb of his other hand over it, sending a shudder down Luigi’s spine. “Deep too. He couldn’t breath and he bled what seemed to be most of if not all his blood out. I even stopped his heart. And yet, he wouldn’t die.”

“You bastard!” Mario grabbed King Boo by the shirt and shoved his back roughly against the wall. He reared a fist back for a punch but seemed to catch himself just in time to punch the wall next to Luigi’s head instead of Luigi himself. “How _dare_ you?”

With in inward chuckle, King Boo surrendered control to Luigi. Mario pushing him against the wall was suddenly the main thing keeping him up right as he shook from just the _memory_ of that incident. It made him nauseous but he could almost recall what it felt like to lie there, bleeding out but not dying, not even passing out.

Mario jerked back with a stricken look. “I’m sorry Luigi, I didn’t mean to…”

“It’s fine,” Luigi interrupted. “I uh… just don’t want to think about… that.” He wanted to say more but…

Having had his fun messing with Mario, King Boo took control back; steeling against the trembling and even pushing down the growing panic and forcing away the memory of it which Luigi wholeheartedly welcomed and assisted in. He then put a hand on Mario’s shoulder to push him to the side a bit to stroll past him. “Why did that happen?” he asked he strode over to stand in front of E. Gadd. “Why can’t the meatsuit die?”

E. Gadd looked shocked but quickly recovered, shaking it off before replying. “Hmmm… well I can’t say for sure without more data but my hypothesis would be that it has something to do with your souls merging. One of your souls is dead while the other is not, together you’d be something that’s sort of in-between, right? Meaning you’re neither fully alive nor fully dead and thus you can’t die. Oh uh… you may have actually discovered the secret to immortality, congrats! Hmm… I wish I could run all sorts of tests and experiments on you but… I _can’t_. My lab’s in shambles and there are lines I won’t cross even for science, letting a friend’s soul merge with someone so vile is one of them. I need the prioritize finished the KBE above all else.”

Luigi could’ve hugged him for that and with all he’s been through lately, he probably would’ve if King Boo wasn’t there to restrain him. … That hug with Mario had been more than enough for the day, King Boo refused to tolerate any more. So Luigi had to settle for a shaky, “Thank you,” instead.

E. Gadd grunted an acknowledgement as he spun his chair back to face his desk. “Speaking of that, I have work I need to get back to. Revealing your… _stunt_ reminded me just how urgent his is.”

Unhappy but satisfied with that answer, King Boo turned back around to grin at Mario who was back to looking mad. “As soon as you’re out of my bro’s body, I’m gonna make you pay for everything you did to him,” he said, making it sound like a promise.

With an evil chuckle, King Boo raised an eyebrow. “Really? And how do you plan to do that? We’ve fought before, remember? Three times now. I won easily every single time. If it wasn’t for your bro here, you’d still be wall art.”

“I don’t care. You’re going to pay.”

Luigi wished he could take comfort in that but… he just couldn’t. Mario didn’t stand a chance against King Boo; three times were certainly enough to prove that. Maybe if he had a Poltergust he would but even then, he didn’t know how to use it, did he? It didn’t match his style of combat at all.

‘ _If he tries anything, he’s doomed._ ’ … So hopefully he wouldn’t. If he did, Luigi would have to try to convince him not to. But that was thankfully something he didn’t have to worry about right now, getting free of King Boo came first.

Over the next however long, they sort of just hung out at the lab. E. Gadd worked, only occasionally calling Gooigi over to help with something. He called King Boo and Luigi over once for one more scan just for the sake of it and to see if anything had changed; it hadn’t. Other than that, none of them had anything more they could do right now but seemingly nowhere else to go.

It was Mario who eventually pointed out how late it was. Neither Luigi nor King Boo had noticed beyond taking note of Gooigi falling asleep in the corner but it was nearing midnight. King Boo’s magic and seemingly the whole half dead, half alive thing reduced their need for sleep – and other life sustaining things like food and water – making it easy to lose track of how late it was.

“Rest is for those without coffee,” E. Gadd protested upon the suggested he should rest and continue tomorrow.

Mario frowned at him. “While I agree, this is _very_ important and needs to be done as soon as possible, it’s probably better if you rest.”

“I agree,” King Boo said. “If you fuck this up because of sleep deprivation or any other reason, I’ll make you death a slow one.” As much as he’d like it if E. Gadd could work on it 24/7, even he knew that the living needed sleep or they didn’t function properly. He’d rather it take a little longer to ensure E. Gadd did it right then rush it and probably result in something in it not working right and thus the whole thing failing.

E. Gadd groaned and complained in a way that was almost funny before finally spinning around and hopping off his chair. “Fine whatever. Let’s all get some rest. Goodnight.”

“Goodnight.” Mario said as E. Gadd walked off. He then turned to look at King Boo and Luigi, still leaning against a wall to the side. “You want to come back to the castle with me? It’s a shorter drive back here than to your old place. And we can car pool.”

“You… really want me coming back with you?” Luigi asked because anywhere he went, King Boo went too and no one in their right mind would invite King Boo over to their house.

‘ _Wow, rude! I’m perfectly good company._ ’ … That was so blatantly untrue it wasn’t even worth a response. … ‘ _When I_ want _to be I am._ ’

“Of course I do, your my bro. Even if you got an uh… unwelcome passenger right now, you’re still welcome over.”

“Let’s go then,” King Boo said as he stood up. He was bored and sleep sounded nice right about now anyway even if they didn’t feel much need for it yet.

Mario didn’t live in the castle itself – though he did have a room there that he stayed in sometimes – but a house very near it. Luigi had lived with him there until a few years ago when he’d decided to try to be a little more independent. Which actually was part of what had led into the original haunted mansion trap so maybe it hadn’t been such a good idea after all.

Regardless, the place was almost exactly how Luigi remembered, the red couch in front of the outdated TV, the kitchen doorway to the right, and the hall leading to the bedrooms, except messier. Mario had never cared much about tidiness the way Luigi did. … King Boo preferred tidiness too. … Finally, something they had in common so at least when their souls merged, whatever kind of person they’d become would still be neat and tidy.

‘ _No need to be so pessimistic._ ’ It dampened King Boo’s confidence that this would turn out fine.

_Can you blame me for being pessimistic when you’ve been making my life a living hell for however long we’ve been like this?_ Honestly, as bad as the idea of their souls merging into one was, it would probably be better than continuing to exist with King Boo in control of his body. _So I think I’m allowed to be as pessimistic and negative and whatever else I want however much I want._

‘ _You should really stand up for yourself more. It’s more exciting than your whimpering and cowering is._ ’ Though part of why it was exciting was that the whimpering and cowering had gotten old after being exposed to it for so long.

_Fuck you too._ Even if he wasn’t physically tired, he was mentally and he just wanted this nightmare to be over with already. He’d reached the end of his rope a long time ago. That earned a chuckle from King Boo, before he could properly reply though…

“You okay?” Mario asked, stepping in front of them.

“No,” they said out loud together because it was impossible for them to be okay in these circumstances.

“Anything I can do to help?”

“Unless you’ve been hiding a way to get me out of this meat suit, then no, you can’t help,” King Boo replied.

Mario glared at him. “I wasn’t talking to _you_.”

“It’s fine Mario,” Luigi cut in before King Boo could reply with a snarky taunt. “I’ll be fine… hopefully. I trust the professor, if anyone can fix it, it’s him.” What if he couldn’t though? What if it was too late already? Or too late by the time he finished the KBE?

“Yeah, you’ll be free of King Boo soon, I’m sure, just got to hang on a bit longer.” Mario gave him an encouraging smile. Luigi had always been a little jealous of his confidence.

Ignoring him, King Boo strode past him towards the bedroom. For the sake of getting along… ‘ _Which room is yours?_ ’ He was tempted to head for Mario’s room to mess stuff up but it would accomplish nothing.

_The one on the right._ Luigi wouldn’t have let him mess with anything anyway.

“Uh… goodnight then Luigi,” Mario called after them as King Boo started down the hall. “Sweet dreams.”

“’Night Mario,” Luigi returned before King Boo could close the door.


	9. Turns

**Notes for the Chapter:**

> For the sake of my sanity, I'm splitting this chapter into two parts because after all the heavy edits I performed on it, it was way too long and there was already a convenient cut point in the middle anyway.

Waking up in his old room was very odd. It was bare, the shelves empty and the walls free of decoration but the glow in the dark stars he’d stuck to the ceiling shortly after moving in were still there and the comfy bed with its green bedspread felt the same. It felt wrong to be in a place he used to feel so safe and cozy in with King Boo in his body, making everything so awful.

King Boo scoffed internally at that as he dragged them out of bed. They would both rather stay sleeping but even with the aid of magic and willpower they could only sleep for so long. Luigi would’ve been content to stay lying in bed, pretending to sleep, but King Boo wasn’t having it so up they got.

Stepping out into the hall, they almost ran into Mario. He jumped back, putting on a smile. “Good morning Luigi.”

“Good morning,” Luigi replied even as King Boo ignored them both as he headed straight for the living room.

Once there, he paused and glanced around until he spotted the phone. ‘ _What’s E. Gadd’s number?_ ’ he asked, as he beelined for it.

Luigi gave it to him as he dialed it in.

It rang twice before someone answered it. “Hello!” It was Gooigi.

“I need to talk to E. Gadd,” King Boo said before Luigi could try to return the greeting.

Gooigi mumbled something in reply followed by a call for E. Gadd. A few seconds later the sound of the phone changing hands occurred.

“Who is it?” E. Gadd asked from the other side, his tone mildly annoyed.

“Any more progress on your machine?” King Boo asked, not wasting time with being polite.

“Nothing significant and your call is only slowing me down.”

“You need us down at the lab for anything?” There probably wasn’t anything either of them could help with at this point but Luigi might as well cut in and ask to make sure anyway since they were already on the phone with him.

“Hmm… not right now. I’d like you down here later tonight though. I might be able to measure how fast your souls are merging if I can scan them around the same time each day. So, I’ll see you later tonight, an hour or so after the time you show up yesterday. For now, goodbye.” He hung up.

King Boo hung up too before turning around to frown at Mario who was standing behind him.

“Any news from E. Gadd?” he asked.

King Boo mentally nudged Luigi to answer because he didn’t want to talk to Mario if he didn’t have to. So… “Not really. But uh… he wants us back at his lab later tonight to try to measure how fast the uh… soul thing is happening.”

“Well, I supposed that’s to be expected. What are we going to do in the meantime?”

Luigi opened his mouth to answer but… he didn’t know. It was still early morning, they had _hours_ before they were needed at the lab.

‘ _Does your brother keep any alcohol in the house? Or perhaps other ways to make time seem faster?_ ’

Luigi would’ve been tempted to go along with that idea – anything to dull his misery _and_ make the passage of time feel faster – if it wasn’t for Mario. In general Luigi would rather never be seen while overly intoxicated on any substance but with Mario it’d be even worse. So… _No, we’re not doing that_.

King Boo frowned. ‘ _How ‘bout I do it anyway? If there’s none in the house, I’m sure we could find some elsewhere._ ’ Even before completing the thought, he was already headed for the kitchen; the most obvious place to look for alcohol.

He only took two steps though before Luigi tapped in his magic – he was getting better and more used to that each time he did it – and stopped him from taking another. Excepting it this time, King Boo managed to keep his balance this time, he did stumble a little though.

“You okay?” Mario asked as he walked around to stand in front of them.

‘ _What do you propose we do then, huh?_ ’

_I don’t know, just_ not _that, okay?_

If not cooperating was a viable option King Boo would’ve told him to fuck off and do as he pleased anyway. But as it was, he had no choice but to acquiesce for now. ‘ _Fine! But just so you know,_ I _refuse to let you make all the calls about what we’re going to do or not do until the machine is done, got it?_ ’ While he didn’t have full power over Luigi anymore, he still had a lot and could definitely make his life a living hell if he tried pretend like he was in full control now.

It was Luigi’s body though so… Luigi didn’t even let himself finish that thought because King Boo didn’t care. … Yep, he was here and stuck so Luigi was going to have to deal with him for a while longer. … Which meant they’d have to make some kind of compromise if they wanted to maintain their peace agreement.

‘ _All right, how about this: we don’t get drunk or high off our asses but otherwise, I call the shots._ ’

_No_. Luigi wasn’t going let himself be walked over any longer. _We can take turns choosing how we want to spend our time._ It was the fairest they could probably be about this and hopefully it would only be for a few days. Though that was unlikely, it’d probably be at least a week if not more.

King Boo sighed and groaned, he didn’t like that idea but… ‘ _Fine, whatever._ ’ It would guarantee him some time to do as he pleased without having to fight Luigi for it. Though he’d have to do the same back which was lame. This whole playing nice thing was even worse than he’d thought it be. When he was free of this, he was never _ever_ going to possess anyone or even anything ever again. … Good! As far as Luigi was concerned, he never should’ve in the first place.

Pushing aside King Boo’s answering annoyance, Luigi turned his attention back on Mario at last. He was watching them with a slightly worried expression on his face.

“We’re uh… fine,” Luigi said, forcing a smile. They were about as fine as they could be given the situation. “We decided to take turns on deciding what to do to pass the time. It’s my turn first.”

‘ _I never agreed to that!_ ’ … Luigi didn’t care, he’d already spoken so for once, he was going to make things go his way here. In large part because he just wanted to spend some time with Mario. He deserved that after everything he’d been through lately, right? … ‘ _I don’t see why he’d want to spend time with_ you _._ ’ … Luigi was _not_ going to reply to that or dwell on it.

“… but it’ll have to do for now until we can get rid of him,” Mario was saying as Luigi focused back in on him. “Which will be soon I’m sure. So uh… what do you want to do?”

“He wants to spend time with you,” King Boo cut in with a derisive tone before Luigi could answer. “It’s pathetic.”

Mario scowled before putting on a smile. “We can hang out. We’ll just ignore him; pretend he isn’t there.”

“Good luck with that.” King Boo scoffed. “Letting him do as he pleases, doesn’t mean I’m going to stay quiet in the background.” Not surprising, that’d be far too much for Luigi to even hope for let alone expect from King Boo. He’d have to take what he could get.

Mario didn’t respond though, not even with a glance as he turned towards the kitchen. “Let’s have some breakfast and then we can hang out and play video games for a while, it should be fun.”

‘Fun’ was harder to have with King Boo’s grumpiness about everything bleeding into Luigi’s feelings. And his occasional mean comment, both out loud to Mario and internally were a bit of a downer too. Luigi did his best though. And Mario, always the best bro ever, ignored everything King Boo said, somehow always knowing when it was him talking. How much it annoyed King Boo was honestly pretty funny at times especially since he didn’t want either of them to know it affected him any.

Overall, despite King Boo and his best efforts, it was definitely the best day Luigi had had since the start of this nonsense – not that there was much competition for even a good day, let alone the best. They played video games and watched some TV together, eating junk food. It was almost like the good old days before they’d gained any real responsibilities or learned how cruel the world could be. Back when they’d been nobodies; not heroes or anyone’s rival or anything else, just a couple of bros who’d gone into the plumbing business together.

Alas, as with all things, it had to come to an end at some point. Eventually it came time for them to go back to E. Gadd’s lab. Mario drove while King Boo decided to take a nap lying in the back seat. Neither Luigi nor Mario approved of the no seat belt necessary for that position but King Boo didn’t care and it wasn’t worth fighting over much so he got his way.

Gooigi greeted them at the door when they arrived, answering the bell within seconds as if they’d been waiting for them, probably at E. Gadd’s request. Immune to Polterpup’s barking, they lead the way into the lab proper.

The boxes and piles of junk had been moved, allowing for the beginnings of a new invention to be built to the left. It wasn’t much but it was a start. Hopefully when it was finished, it would work.

E. Gadd was already setting up the scanner again. Making it easy to quickly get to the reason for their visit without even exchanging greetings of any sort.

“Your souls are definitely more merged than they were this time yesterday,” he said a short time later, not even looking up from the scanner readout on his laptop yet. “I don’t think it’s a worrying amount though, not yet anyway. I want to keep a close eye on it though so come back this time tomorrow. But for now, shoo.” He closed the laptop as he stood up, making a shooing gesture with one hand at them. “I need to get back to work.”

King Boo had no complaints about that so with a shrug, he turned and strolled out of the lab. Luigi would’ve preferred to hang out a little bit, make sure all was going well and help out with anything if it was needed but… ‘ _It’s my turn now._ ’ And King Boo didn’t want to stick around so they weren’t.

“Uh… be sure you’re not overworking yourself or anything,” they heard Mario say behind them before he ran to catch up with King Boo as he exited the building entirely.

“Drop me off in town on your way home,” King Boo said to him without even glancing his way as they headed back towards the car. “I have some stuff I need to take care of.”

“You really think I’m going let you run off by yourself again?”

“Yes, actually. That’s part of the deal I made with your brother, remember? I let him have fun with you, now it’s my turn to do whatever I want. He’ll be the one to pay for it the most if you try to stop me.” Completely confident that Mario would do as he said, King Boo climbed back into the backseat of the car. After closing the door in Mario face, he lay back down and threw an arm over his eyes to block the light.

A few seconds later, Mario climbed back into the front, slamming the driver-side door hard enough to shake the whole car. “Fine, but I want him back home before midnight.”

“I’ll have him back not long after sunrise tomorrow, no sooner.”

Luigi would rather not stay out that long but they did need less sleep now so it wasn’t the end of the world. And it would give him plenty of time to spend with Mario tomorrow. So… “I’ll be fine bro, don’t worry about me,” he said before Mario could try to protest. “He already agreed not to… do anything bad or… you know, so it’ll be fine.” Or at least as fine as it could be.

“All right, I guess.” Mario still sounded unhappy about it as he started the car. “I suppose it’s not like he’s gonna run off anywhere anyway.”


	10. King Boo's Turn

In town, King Boo’s ‘stuff that he needed to take care of’ turned out to unsurprisingly be buying more of his fancy suits. He was into looking stylish so as long as he was stuck in a meatsuit he was going to dress as such. He even considered getting a fancy dress as a change of pace but chose not to because he hoped not to be stuck like this for much longer.

Luigi would be lying if he said King Boo didn’t have good taste. He would’ve chosen different colours personally but the white and purple matched well with the white hair and purple eyes that came with King Boo’s possession of his body. Now that he was more used to that appearance, he’d almost be willing to say that it wouldn’t have a bad look at all if he’d chosen it for himself, not that he probably ever would’ve especially for an everyday look.

‘ _So you admit it? I’m cooler than you in every way?_ ’ King Boo said with a smirk as they looked at themselves in the dressing room mirror.

_I guess._ It wasn’t really hard to be cooler than Luigi, he’d always been pretty lame. In large part because being cool had never mattered to him. It still didn’t so honestly, King Boo’s taunt wasn’t that hurtful, especially after all the various other ways he’d hurt Luigi.

King Boo frowned as he turned away to leave. ‘ _Whatever, then._ ’ He didn’t really care all that much anyway.

The sun was starting to set as they came about to the rear of Peach’s Castle. King Boo had gone rather far out of his way to sneak around behind it after the taxi had dropped them off near it. Now he frowned at the rear wall, cutting off the back garden from the rest of the land. Not being able to phase through things never ceased to be annoying.

Instead, after adjusting his shopping bags on his shoulder, he pulled on his magic and levitated them. It wasn’t the first time he’d done this but Luigi still hated it, flying was not something he’d ever wished to be able to do. But in honor of their agreement, he refrained from directing an actual complaint towards King Boo as he lifted them up and over the wall. By some miracle, he even had the courtesy to lower them gently to the ground once on the other side instead of letting Luigi’s body drop and probably sprain or break something as he’d done every other time he’d levitated them any significant height in the past.

Thanks to the wall surrounding it, the courtyard garden area was already shrouded in darkness. With the gentle sound of the fountain in the middle it was still a pleasant place though. Or at least it was until a boo came shooting out of the nearby bushes.

Even expecting it due to King Boo having thought about meeting with boos at the castle multiple times since his turn had begun, it still surprised Luigi. King Boo didn’t let him flinch though, honestly at this point, the fact that he would’ve was just shameful. … Luigi was inclined to agree for once, he couldn’t help it though.

“Boss!” the boo said as he to a halt in front of King Boo and Luigi. “You’re here!”

“Yep.” King Boo smiled at him, one of those genuine smiles that still creeped Luigi out far more than the evil ones ever did. ‘ _I like my boos, why is that so weird?_ ’

_Because you’re_ you _!_ Luigi never would’ve thought someone so vile and hateful could care for anyone other than himself. He never would’ve believed it to be the case if he didn’t feel it for himself. After the initial jump scare, he even wasn’t nearly as frightened by the boo as he should be because of how King Boo felt about him.

Other than an internal scoff, King Boo didn’t bother with a reply, turning his attention back onto the boo, patiently waiting to be addressed in front of him. “Gather the rest of the castle boos out here, I’d like to talk to all of you.”

“On it!” the boo said before rushing off again.

‘The rest of the castle boos’? Did that mean that there were boos that hung out around the castle all the time? That… couldn’t be right, could it? There was nothing for them here; Luigi had worked with E. Gadd long enough to know ghosts and boos didn’t like places full of life which Peach’s castle definitely was. So why would they be here? And… how _long_ had they been here?

‘ _A while._ ’ King Boo was particularly proud of the castle boos, they dealt with being near the living and refrained from making mischief enough that they were never found out. ‘ _And you’re not going to tell anyone about them._ ’ He’d rather not out their existence to Luigi at all but he needed to tell his boos what was up with the current situation in case things went bad. These were the closest boos and one of them could be sent as a messenger back to the mansion and from there soon all his followers would know of his predicament. As their king, it would affect them if his soul were to be merged with Luigi’s and thus they had a right to know which overrode Luigi’s need _not_ to know of the castle boos. ‘ _My agreement to play nice ends if you even try to hint at their existence, got it?_ ’

_I won’t tell._ Luigi promised because King Boo wasn’t making an empty threat. They clearly weren’t causing trouble anyway so it was probably fine to let them be for now.

The boo returned a few minutes later with four more. They settled in a half circle around King Boo and Luigi.

King Boo took a deep breath and put his hands behind his back before addressing them in a formal tone. “As you may have heard by now, I’m currently stuck in this meatsuit. The reason for that is: my soul is in the process of merging with his. Meaning if it can’t be fixed, we’ll essentially become a single being instead of two. I’m working on getting it fixed though so it should be fine but in case it’s not, you guys need to know. When this meeting is done, one of you will head back to the mansion to inform everyone, just in case. Now, report to me about the goings on around the castle, it’s been a while.”

The five boos exchanged nervous looks before seemingly accepting that it would indeed be fine as the one on the far left started speaking. He spoke of rumors he’d overheard and events he’d witnessed. When he was done speaking the boo next him started without prompt, sharing similar things. It wasn’t until the third boo was reporting that Luigi finally pieced together that they were spies.

Honestly it made perfect sense. They could become invisible and phase through walls and objects, making it easy for them to stay undetected while being able to see and hear everything that went on in any given room.

A shiver ran down Luigi’s metaphorical spine as the full scope of that realization sunk in. Whenever he’d gone to the castle, typically with Mario but sometimes by himself too, he could’ve been being watched by boos the entire time and probably _was_ while never suspecting a thing. Heck, anytime he’d been _anywhere_ that didn’t have ghost detecting equipment available – which was the vast majority of places – there could’ve been boos around watching his every move even in his own _house_.

‘ _Yep,_ ’ King Boo said with a chuckle, quickly pulling his attention off his boo to reply. ‘ _There were two in your house up until you got Polterpup, he made it much harder of them to spy on you effectively._ ’

Welp, that was awful. Polterpup was without a doubt the bestest boy though. Luigi would’ve preferred to have gone his whole life without ever learning that there were boos who’d been assigned to spy on him. Assuming he got out of this mess, he was going to be paranoid about this for forever. He’d have to take Polterpup with him everywhere to ensure that there were no boos or ghost in the area … As far as King Boo was concerned, that was awesome.

_Fuck you too!_ That only made King Boo laugh though before he pushed Luigi’s thoughts aside to go back to paying full attention to his boos. … Despite how weird and creepy it was, his love for them might’ve made Luigi hate him a little less if it wasn’t for the whole possession thing and the things it had led to.

During the final boo’s report on the rumors going around the castle that involved Bowser, the backdoor leading into the castle opened. All five boos went silent instantly as they turned to look. It was… Peach.

She froze halfway through closing the door behind her. Her eyes locked onto King Boo and Luigi, seemingly looking straight through the boos between them. It was like she didn’t even see them. … Of course she didn’t, they were invisible, Luigi could only see them because his soul was tied to King Boo’s. … That actually made sense; that’s how Polterpup always knew when there were boos and other ghosts around, he could see them even when they didn’t want to be seen.

“Uh… hey Peach,” Luigi said with a forced awkward smile that didn’t match the confident but relaxed pose King Boo held his body in. “What are you uh… doing out here so late?” He struggled not to look at the boos as they moved off to side.

At his voice, Peach jerked back into motion. After closing the door, she strode closer until she stood right in front of him. “Luigi?” She squinted at him suspiciously, crossing her arms.

“Yep, it’s me and…” King Boo naturally stepped with barely even a pause, “me too.”

The look on her face made it clear she knew what was up. “Give him back this instant or else.”

“Or else what? You’ll hit me, go ahead.” King Boo grinned as he spread out his arms and hands, opening himself up to a slap or a punch.

Peach almost looked like she was tempted to but thankfully didn’t. “Well… give him back anyway. It’s been far too long, you’ve had you fun, now let him go. That has to be what you came here for anyway, right?”

“That’s uh… not quite why we’re here,” Luigi said as he put his hands back into his pockets and looked down at the ground between his shoes to keep from glancing at the boos still silently watching. He’d didn’t want to give them away by accident when King Boo’s agreement to get along was at stake.

King Boo immediately looked back up. “For what it’s worth, I would _love_ to ‘give him back’ as you put it. But I fucking _can’t_. I’m stuck in here and our souls merging, it’s _awful_.”

The anger on her face softened, shifting a little to confusion. “You’re… you’re just making excuses, right? You can’t actually be stuck.”

“No, he’s uh… very much stuck,” Luigi said. “E. Gadd’s trying to fix it though.” Key word being ‘trying’ because it wasn’t guaranteed.

“Well we have to tell Mario then; he’s been worried sick about…”

“He already knows,” King Boo interrupted.

“Really huh? It seems he forgot to call and tell me.” Peach frowned, looking none too pleased about having been left out of the loop. Which was a fair point, Luigi hadn’t even considered telling her until just now. “Though, I suppose it’s probably because he’s got a lot on his mind. Whatever, I’ll talk to him about it later. For now, you said your… souls are merging? What does that mean?”

Annoyed with her presence and not wanting to explain it again, King Boo left it up to Luigi this time. “Well uh… it means our souls are… becoming _one_ soul so we’ll be not separate people anymore but like combined one or something.” It was still such an odd concept to think about. What would that _be_ like? They’d basically be a whole new person, right? With how much their personalities and feelings about things were opposites what kind of person would they end up being? “It’s uh… really scary.”

Peach grimaced for a second, biting her lip a little before putting a smile. “That sounds terrible but you said E. Gadd’s working on so it should be fine. You’ll be free of King Boo in no time, I’m sure of it.”

King Boo frowned at her, curling his lip up in disgust. “You’re like that too, huh?”

“Like what?”

“All… mushy and gross, trying to comfort Luigi. Mario does it all the time, it’s annoying. It doesn’t even work all that well so just stop already.”

Peached gasped as if deeply offended. She glared daggers at King Boo as she took a deep breath before responding. “Fuck you too King Boo, I’ll comfort Luigi if I want to.”

Wait? Did she just swear or had Luigi misheard her? He’d _never_ heard her swear before. To be fair, King Boo deserved it but… still, what the heck?

“Now Luigi, sweetie,” Peach continued in a sweeter tone, “E. Gadd is going to get rid of that big bad meanie King Boo and then everything’s going to fine again. I’ll even bake you a cake to celebrate it, whatever kind you want. You’ll just have to hold on until then. You’re strong and brave so I know you can.” She was clearly laying it on a bit strong to annoy King Boo but honestly that made it better.

“Thanks,” Luigi said. Before he could try to say more or before Peach could respond, King Boo made a loud gagging noise to fully emphasize his disgust. This was supposed to be _his_ time to spend doing whatever _he_ wanted to do, not more ‘comfort pathetic scared Luigi’ time.

“Don’t listen to him Luigi, he’s…” Peach began before King Boo cut her off.

“We’re leaving, goodbye.” He snapped around to stride back closer to the wall.

“You most certainly are not,” Peach said as he activated his magic to levitate them again. “Get back here this instant.”

“Uh… I’ll be fine,” Luigi said because he didn’t want her chasing after them. “Call Mario, he’ll explain stuff.” And that was all he had time for before King Boo was lowering them onto the other side of the wall, faster than was necessary, making Luigi a tad queasy, but thankfully not a full drop.

Having been able to just phase through the wall, the boos were already waiting for them. King Boo landed in their midst.

“You,” he said pointing to the smallest one, “You’re the fastest, so you’re delivering the message to the mansion. The rest of you, I got until about sunrise before I have to leave, let’s make the most of it.”

The appointed messenger left without a word, zooming presumably in the direction of King Boo mansion. The other four fell in ‘step’ with King Boo as he strode away from the castle walls into the small forest behind it.

Not long ago, Luigi would’ve been worried they were going to cause trouble. But now, even when King Boo wasn’t actively thinking about it, he was at least partially aware of his intentions and they weren’t nefarious for once. He was going to play chess with them, using the chess set he’d brought at the mall alongside the clothes earlier. It wasn’t a game Luigi liked but it was far better than the other ways King Boo could’ve chosen to spend his turn so he’d take what he could get.


	11. The King Boo Exorcist

Over the next few days, they settled into a sort of rhythm. The morning and midday hours belonged to Luigi which meant hanging out with Mario and sometimes Peach now that she knew what was up too. The evening and night hours were King Boo’s which meant wondering around town and/or the forest outside of Peach’s castle before spending some time with the castle boos. Or in one instance, King Boo managed to convince Luigi to let him drink the evening and part of the night away; it was hard to resist the urge to dull the mind and forgot everything for a bit.

King Boo’s turn always began as soon as they were on their way to E. Gadd’s lab. Mario always drove them while they napped in the backseat. The frequent trips to the lab allowed them to keep track of the progress E. Gadd made on the KBE. It was far slower than either of them was pleased with, given the stakes, but it was something.

A week into it E. Gadd had a bit of a different report after reading over the results of his scan. “It’s accelerating,” he said, frowning at his laptop.

Everyone in the room froze. It was King Boo who broke the silence. “What do you mean?” He had a good guess but he really wanted it to not be true, to me a misunderstanding instead. Luigi couldn’t agree more, so much so he couldn’t separate his feeling from King Boo’s.

“I mean, your souls are starting to merge faster because the more they merge, the easier it is for them to do so. I’ve suspected it from the very beginning but I didn’t want to say anything until I knew for sure.”

Luigi gulped, turning his head to look at the KBE again. Neither he nor King Boo knew much about such things but even they could tell it was still a good way from being completed. … Meaning release from each other was still a few days away at least, probably more. … Assuming it happened at all.

King Boo growled. Of all the people for him to end up like this with, why’d it have to be someone so anxious and worried about everything because those feelings got to _him_ too now. He was supposed to just be aware of them but instead they made _him_ all worried and anxious that’d he’d be stuck in this meatsuit for forever.

_You think_ you _have it bad, what about_ me _?_ _I’m stuck with an evil asshole who tried to kill me and enjoys making me suffer._ That was so much worse and _so unfair_. Luigi hadn’t asked for _any of this_. Right from the very start he’d just wanted to live his life and have nothing to do with ghosts of any sort. He wouldn’t ever have had any beef with King Boo in the first place if King Boo had never trapped Mario in a painting that first time. So, King Boo had _no_ right complain when it was entirely _his fault_ in every possible way.

‘ _If you’d just let me turn you into a painting at any of the times you were_ supposed _to none of this would be happening either._ ’ Or Luigi could’ve just stayed the fuck out of it to begin with and let King Boo have Mario then…

_No, I’d never let you take my bro. Fuck you for trying!_ Luigi wasn’t a hateful person, he’d never hated anyone before, but he was far beyond his limit as this point. If he could, he’d kill King Boo on the spot with no regrets, heck it’d probably feel really good.

King Boo scoffed. ‘ _Even if it was possible, you wouldn’t be able to do it. You’re too weak and pathetic._ ’

_I beat you_ three _times! I could do it._ And oh how he wanted to, the _only_ thing stopping him was the fact that it was impossible. _I could mop the floor with…_

“Luigi!” Mario stood in front of him, gripping his shoulders and looking at him with a concerned expression. “You okay?”

Feeding off each other’s rage in a loop, Luigi’s body was shaking with it, his hands balled up tight enough to hurt a little, his jaw clenched. Having realized this, he was filled with the urge to hit or smash something. How much of that urge was his, if any, and how much was King Boo’s he actually couldn’t tell. King Boo didn’t care, he wanted to punch Mario. He would’ve too if Luigi hadn’t stopped him.

“No, I’m not okay,” Luigi forced out. “I hate this.” The anger and the urge to damage or _kill_ something with it was scary. He wanted it to stop and he wanted to go home.

“I know, I’m sorry.” Mario put on an encouraging smile. He was really good at those but it still didn’t help much. “E. Gadd’s doing his best to fix it though so it’ll be okay. I know it’s hard but just hang on a bit longer, you’ll make it through this, I promise.”

“What if he can’t fix it though? What happens then? What and… and _who_ would we even _be_ at that point?”

The question, not spoken aloud until now, brought silence from everyone, even King Boo. No one knew for sure what exactly would happen once their souls were fully merged, only that that there would be no going back from it.

“Don’t worry about it,” E. Gadd finally broke the silence. “I’m an expert in this stuff, I’m confident the KBE will work.”

He sounded so sincere and for him, caring. Luigi desperately wanted to believe him and would’ve without a doubt even just a few weeks ago. But after all King Boo had put him through on top of this soul merging thing, he couldn’t quite fully believe that things could take a turn for the better at this point. It was like the universe or god – if such a being existed – got some kind of cathartic enjoyment out of watching him suffer.

But he nodded anyway, forcing out a “Thanks,” to cover up the fact that he was still scared and _angry_ that he was scared.

After that, E. Gadd did need one more part for the KBE. They tagged along with Mario to pick it up from the fellow he’d ordered it from which resulted in a long car ride and not much more. King Boo had been hoping for an adventure in part for a little bit of excitement and change of pace but also because he’d heard of the other adventure Mario and Luigi had gone, they sounded like they could be fun.

_You wouldn’t like them; they involve being a good guy and saving people._ Luigi told him as they lay in the backseat of Mario’s car during the drive back.

‘ _We’d have joined the bad guys of course and helped them win and then we’d double cross them and turn them into a painting._ ’ That way the only people winning would be the two of them. Chaos for the sake of it was fun and King Boo was bored of playing nice with people he didn’t like.

Luigi could only sigh at that. An adventure might’ve been fun though, but with King Boo along for the ride it was best they didn’t have one.

Soon, even without E. Gadd’s declaration about their souls starting to merge faster, they would’ve been able to guess it for themselves. Thinking the exact same thing at the exact same time, once a rare occurrence, began happening more often. Their emotions affected each other more and more, often bleeding together entirely until neither of them knew where theirs ended and the other’s began. And sometimes, very occasionally but it happening at all was worrying enough, neither of them were at all sure who a thought or emotion had even originated from.

“I’m scared,” Luigi admitted to Mario one morning after breakfast. He was extra miserable because he was still a little hungover; more and more did he give into his own desire to forget backed by King Boo’s. He held the line steady at nothing beyond alcohol though and in making sure Mario never found out.

King Boo scoffed at his admission but didn’t care enough to interject. … _You’re scared too, you just don’t want to admit it._ … King Boo could only growl in response because it was true. ‘ _It comes from you though._ ’ All of it for sure… maybe, King Boo wasn’t entirely sure anymore and he _hated_ that that was the case.

Mario had of course replied with an encouraging smile like always. Luigi felt bad for not paying attention but it was hard to do when his mind was so busy with two people’s thoughts.

“You need anything?” Mario asked. If he knew Luigi hadn’t heard him, he showed no sign of it.

“I just want this to be over with.” More than anything, they both did.

“It will be soon.” It indeed should be because the KBE was almost done as they’d seen yesterday. If it didn’t work though, would E. Gadd have time to rework it to _make_ it work? … Hopefully they wouldn’t have to worry about that.

Two days later E. Gadd himself greeted them at the door instead of Gooigi and Polterpup. “It’s done,” he said, his voice brimming with excitement.

They’d of course expected this soon but it was still great news. “Finally,” King Boo said as they stepped inside. He fast-walked to enter the lab proper where Gooigi and Polterpup were. He ignored them and went straight to the KBE.

Painted red and taller than Luigi by several inches, it had as cylindrical shape. There were buttons, a keypad, and a screen on the side facing the rest of the lab. What seemed to be its front had a mechanical opening, currently closed, and a large red button next to it. Not knowing how it worked, neither of them dared to touch it yet.

Mario and E. Gadd took a bit longer to follow, only a few seconds but enough to make King Boo almost hiss with impatience. He wanted out of this body _now_. And Luigi wanted him out _now_.

“How do we begin?” they said together, looking at E. Gadd.

“Before we start,” he said, his voice much more somber now as he strode over to stand before them, “I must warn you that this might not work.”

“We already _know_ that.” King Boo hissed, not liking the reminder. There was no way to know it would work until they tried it.

“Yes, I know _but_ what you don’t know is that if it fails it’ll make it worse. Instead of pulling out King Boo and breaking the link between your souls, it could pull them closer together instead. I’m not sure what the chances of that are, I don’t know enough about this process to say, but I don’t think they’re too high. I do feel the need to warn you of the possibility though.”

Any chance at all wasn’t good given the consequence and honestly both of them would’ve preferred it if E. Gadd hadn’t told them about it at all. But they didn’t really have a choice; this was their only option and only hope to be free of each other so… “All right, how do we begin?” they said together again because they were perfectly united on this front even if it was now a little scarier.

“Wait!” Mario cut in before E. Gadd could answer. “Before you do…” He ran over and… hugged Luigi.

They were both taken aback by it but Luigi recovered first, returning the embrace before King Boo could try to escape it. … He hissed in disgust back thankfully it was over soon.

“You’re almost free,” Mario said. “Everything’s going to be all right again soon. So, don’t worry about _that_ , okay? I know this’ll work.” He was saying it to be comforting but still seemed to truly believe it. And well… how often was he wrong about these things? A few times sure but not often so if he believed it would work then Luigi did too. Everything would finally go back to normal after this, he’d be free. … King Boo would be to and he was _so_ looking forward to it.

‘ _I can’t believe I just let Mario of all people encourage me._ ’ It was gross but whatever, it wouldn’t matter soon anyway.

“Thanks,” Luigi said, giving Mario a smile. “You’re the best.”

“All right, now that that’s done,” E. Gadd said as Mario stepped back to stand by Gooigi again. “Let’s not waste any more time and get this show on the road.” He was back to being excited as he always was whenever he finished an invention.

Turning back to the KBE, he pressed the big red button by the closed opening, making it open with a slick mechanical noise that could’ve come right out of a science fiction movie. Inside was a plain white hollow space and a padded chair bolted to the floor. Attached to the chair were straps, quite a few: on the back, armrests and even legs. It looked like something one would see in a torturer’s chamber.

Despite that, E. Gadd gestured for them to enter. “Hop on in and sit down, I’ll strap you in.”

They didn’t like it but they’d do _anything_ to be free of each other at this point. So, with little hesitation, King Boo sat down.

“This is going to be unpleasant by the way,” E. Gadd said as he began strapping them in, starting with the forehead strap that held their head to the back of the chair. “There’s really no way around it though and I’m sure both of you are you willing to put up with it at this point. But still, I’m sorry I have to put you through this Luigi. Not you though King Boo, you deserve it. Now,” he clapped as he stepped back, “test your bonds for me please. Are they too tight? Too loose?”

Luigi tested them and found that he could not move much at all anymore, really only his fingers and toes. It was disconcerting and already growing uncomfortable but it was without a doubt worth it. “They’re good,” King Boo said, eager to have this done.

“All right sonny,” E. Gadd said as he stepped back further, exiting the machine entirely. “See you on the other side then, hopefully sans King Boo.” He pressed the button again and the opening closed, cutting off Luigi’s view of the lab and its occupants nervously watching.

He took a deep breath as the KBE hummed to life around him a few seconds later. Just a little more awfulness and he’d be free at last, he could handle that.


	12. Free?

He woke up slowly, feeling groggy and heavy. He hated it already and wasn’t in the mood for it. So he rolled over and… fell of whatever he’d been lying on.

Suddenly very much awake, his eyes flew open as he landed on the floor. Thankfully the fall had been short because it was uncarpeted concrete. Awake now, whether he liked it or not, he took a deep breath as he sat up to examine his surroundings.

It was a small room that almost resembled a living room. He’d been lying on the couch in the middle of the room that faced an old coffee table that supported and even older looking TV. Those were the only items in the room other than for a flashlight on the coffee table and a chair placed by the couch. It was from E. Gadd’s lab, meaning this room was probably one of the back rooms that acted as E. Gadd’s living space. Given that, it was unsurprising how sparse the room was, E. Gadd wouldn’t be spending much time in it.

Speaking of the lab though, it was the last thing he remembered. He’d been strapped into the KBE, the door had closed and then… nothing. … Had it worked? …

His mind was quiet; no thoughts but his own, no internal voice but his own, no emotions but his own, and most of all no contention between himself and another being. It was just him alone in his mind and it was _amazing_. Peace and quiet at long last, he’d forgotten what that was like. … There was a problem though.

Using the couch’s armrest, he pulled himself up to his feet. He then looked down at his hands and body; the meatsuit. It felt both right and wrong to have it even if he was used to it by now. … If the KBE had worked, he was supposed to be a free-floating ghost again, right? … No, actually this was right, he was still alive and it was _his_ body and it was _finally_ entirely his again as it should be. … Both of those couldn’t be true and yet they were meaning… … … …

“It failed,” he mumbled aloud to himself, unable to stop staring at his hands. E. Gadd had warned that it might pull their souls closer instead. He was both King Boo and Luigi and while also neither of them. Try as he might he couldn’t find any separation between them in his mind. Their souls had merged into one and that soul was his.

With a heavy sigh, he flopped back onto the couch. He wanted to be angry about this and kind of was but also… his mind was so quiet. No anger but his own, no fear but his own, no fighting with words or for control, no one leeching off his magic anymore, it was finally just his again, just as his body was solely his own again as well. This wasn’t the outcome either side of him had wanted but it wasn’t nearly as bad as he’d thought it’d be. … Both Luigi and King Boo would’ve been horrified and disgusted by it but he didn’t care.

What now though? What kind of existence would he have now? Who exactly _was_ he? He needed a new name for sure, right? Neither ‘Luigi’ or ‘King Boo’ felt right anymore. And… he needed to tell people.

How would the boos react? How would Mario react? What about E. Gadd and Gooigi? Or Peach? Was he still technically king of the Boo Kingdom? Would they _want_ him as their king still? … Would he be abandoned by everyone he’d ever loved?

With an angry growl he stood up and physically shook those thoughts away. He wouldn’t know how they all felt about him now until he told them and if they all didn’t like him and/or didn’t want to follow him anymore then… so be it. He couldn’t blame them for that given the circumstances and he wasn’t pathetic and whiny anymore so he’d deal with it… or he’d try to at least.

Before his thoughts could spiral any further, he glanced around the room and located the door that probably led back to the lab. He strode over to it and carefully opened to peek through.

Yep, it was E. Gadd’s lab all right. And E. Gadd was in. His back was to King Boo/Luigi as he worked on the KBE. Its paneling was open and he was digging around its insides with the help of Gooigi’s flashlight.

Silently as possible, Luigi/King Boo stepped through the door and gently closed it behind him. He crept over until he was right behind E. Gadd and Gooigi, still unnoticed. “Boo!” he shouted, loudly clapping his hands together as well.

E. Gadd startled, making an undignified yelp of surprise before he snapped around. Gooigi didn’t flinch – disappointing but not surprising –they did turn around as well though.

“Luigi!” E. Gadd said, holding a hand to his chest as he let out a breath. “Or I guess King Boo, don’t do that. But uh… you’re finally awake. It’s been…” he glanced at his wrist watch, “almost twenty-four hours now. We were starting to get worried.”

He clearly didn’t know how badly his machine had failed so… “What happened?”

“Well the KBE failed obviously and in doing so it drew too much power and almost exploded. The power surge fried pretty much everything else too, I just got the power back on a few hours ago. The KBE is in a poor state now as you can see but I’m confident that I can get it working again in a day or two and improve it so that it has a higher chance of working this time. So uh… don’t worry Luigi, you’ll be free of King Boo soon still, just a few more days.” He wasn’t very good at being comforting but he was trying and that was nice. Too bad it was for nothing though.

“Don’t bother, you’ll just be wasting your time.” There was no way this could be undone.

E. Gadd had started to turn back to his work but froze. “What do mean?”

“I’ll say it like this: you’re prediction was right, my kindness does outweigh my bloodlust,” in this instance anyway, he doubted that would always be the case, “and thus I have no desire to kill you even if I am mad at you for failing.”

For a second or two E. Gadd looked confused but then with a small gasp it seemed to click. He opened his mouth as if to say something but nothing came out.

It was Gooigi that broke the silence with an “Uh-oh.” Their face was expressionless as always but their voice was distraught.

“Yeah, ‘uh-oh’, indeed,” King Boo/Luigi said with a sigh.

“I’m sorry,” E. Gadd finally found his voice. “I… didn’t… I failed… I’m sorry.” He looked away, pulling his arms in on himself. He was far more upset than Luigi or King Boo had ever seen him before. … There was _no_ excitement about the potential test subject he’d just got; he really did care more for Luigi than his ghost studies. That had already been made pretty clear but… the full confirmation of it was something else entirely. Luigi had had a good friend.

“It’s uh… really not so bad.” Luigi/King Boo forced a smile for him. “My mind is finally at peace. No more pathetic whining and whimpering and no more being hurt or tormented with literally no escape. It’s finally over. This is _far_ better than staying as two separate minds stuck in the same body.”

E. Gadd’s shoulders slumped. “I know but… you deserved better. I thought I could fix it but… I guess not.”

This was the worst. How was one supposed to comfort someone when it was their own existence that was the problem? It was impossible, wasn’t it? So… “Where’s Mario?” he asked because he needed to get the whole telling everyone he cared about that he was a combination of someone they loved and someone they hated before he could figure out what to do next. He wasn’t looking forward to it and part of him would prefer to hide from everyone and everything instead. He’d never liked being a coward and now he just hated it more.

“I sent him out to take Polterpup for a walk,” E. Gadd answered as he abandoned the KBE to sit at his desk instead. Gooigi just sat down on the floor where they were already. “He wouldn’t sleep and he’s been hovering around you a lot so I figured some fresh air would do him some good. He should be back soon though.”

With nothing more to say to either him or Gooigi, Luigi/King Boo strode out to wait in the front part of the lab. He thankfully didn’t have to wait long, not even five minutes passed before the door opened and Polterpup came bounding in following shortly after by Mario.

“Puppy,” King Boo/Luigi greeted Polterpup as he came running up for a pet.

“Luigi?” Mario said, his voice full of worry and hope, making it impossible to stay focusing on Polterpup. Oh gosh, there were bags under his eyes too, he indeed clearly hadn’t slept. “How do you feel?”

“Not too bad actually.”

“Oh, that’s good. E. Gadd said that he can fix the KBE pretty fast and that next time it should work so don’t…”

“There won’t be a next time,” King Boo/Luigi interrupted. “It’d be a waste of time.”

“What do you mean?”

“I _mean_ Luigi and King Boo have become one person and that person is _me_.” He pointed to himself, putting on a slight smirk to hide his true feelings about revealing this. “I doubt it can be undone at this point so refer to me as… ‘Booigi’ should do for now. I might change it later but I need a new name, a combination of my two old ones isn’t a bad choice.”

The despair that took over Mario’s face as those words sunk in would’ve greatly pleased King Boo but King Boo’s hate for him had never been as strong as Luigi’s love. As a whole, the stronger feeling won over, leaving Booigi feeling kind of awful.

The silence stretched as Booigi waited for Mario to say something. He didn’t though, instead he just looked at Booigi, tired and… sad; grieving.

“I’m sorry,” Booigi finally said, letting his shoulders slump. He didn’t want to show weakness but caring for someone wasn’t weak, right? “For what it’s worth though, this is _far_ better than what I was going through before. For both my halves honestly but especially the half of me that is Luigi. I’m not suffering anymore, that’s good, right?” Right now, it was enough for _him_.

Mario thought about it for a few long seconds before slowly nodding. “Yeah, that’s better then… what he was going through before. But… but… it’s just wrong. How could that… happen? I was supposed to… protect him and now…” he trailed off with a vague hand gesture, not even looking at Booigi anymore.

“You need some sleep. What me to take you home?” He needed to go see the boos and ghosts that had followed King Boo for countless years now and tell them the news too but he could take some time to drive Mario home at least.

Mario mumbled something unintelligible in response. With a sigh, Booigi decided to take it as assent. He put a hand on Mario’s shoulder to guide him back out the door.

“You want to come too puppy?” he asked, pausing with the door open to look back at Polterpup. “Come back to where you belong and stop being a traitor?” Ghost animals were rare so he’d be very welcome back at the mansion.

Polterpup whined and got up but it was only to run in a little circle before sitting down again. He probably hadn’t understood the offer but regardless, he clearly wanted to stay here.

“All right, take good care of E. Gadd and Gooigi for me then.”

Mario was asleep long before Booigi pulled up into the driveway of his house. Not wanting to bother with carrying him, Booigi levitated him into the house and to his bed instead. Using the same magic, he even pulled off his shoes and tucked him in. Hopefully he’d sleep for a long time and wake up feeling a bit better about all this… probably not though.

Before leaving, Booigi popped back into Luigi’s old room to gather his clothes and the L hat that had appeared on the bedside table overnight one night. King Boo hadn’t liked it and thus they hadn’t worn it ever but even if it didn’t match his sense of style, Booigi wanted to keep it for old time’s sake.

Luigi’s fear of the haunted woods and King Boo’s enjoyment of them combined into a peculiar feeling. It was kind of like fear but the kind of fear one got while enjoying a horror movie; not necessarily pleasant but not at all bad either. Overall, Booigi would say he liked them but he wouldn’t want to spend a long time in them.

What he _didn’t_ like though was the jump-scare he got when a group of boos jumped out into his path. He flinched and jumped back a little before he could reign it in, _ugh_! Thankfully the boos didn’t seem to notice as they launched right into talking to him.

“You’re back boss!”

“And you’re still in Luigi!”

“We heard about the soul merging thing does this mean that… _that_ happened?”

“It can’t have happened, right? What would we do without you?”

“You’re just here to turn him into a painting, right? Like how you were going…”

“Hush,” Booigi cut in, needing to only raise his voice a little to make them all fall silent immediately. “That’s what I’m here to discuss with you. Gather everyone currently around just outside the mansion.”

Most of the boos seemed to relax, a few seemed to gather that something was wrong though as their worried expressions deepened. All of them obeyed though, quickly scattering.

With a sigh, Booigi continued on. Just telling E. Gadd and Mario had been bad, now he had to tell all his followers. Would they still want to follow him? … Did he still even want to lead them? … Yes, how much King Boo cared for them, dampened the remaining dregs of Luigi’s fear of them. _And_ he still had ambition, not as much as King Boo had for sure, but he wouldn’t be content wondering around doing nothing. He was going to accomplish things, he just didn’t know what anymore.

By the time he reached the mansion, many ghosts had already gathered just outside it, waiting for him. He levitated himself up to float above them all, putting himself in a relaxed posture that he did his best to make look not forced. All their murmuring quieted as everyone turned to look at him. He didn’t say anything yet though, more were still coming.

He hid his not so newfound nervousness well when he did finally address them a short time later when it seemed everyone around was present. “All of you have heard about my situation by now I’m sure.” King Boo had made sure of that. “Every attempt to fix it has failed and now I exist; half your King Boo and half Luigi.”

Audible gasps of course answered that followed by many bursting into questions. There were so many talking at once it was impossible to pick out any one voice.

“Hush.” He had to raise his voice a bit louder this time but it still mostly worked, there were still a few murmurs. “I really don’t know how to proceed from here but…” But what? He hadn’t really planned this speech out, trusting that it would just come to him. That’s how King Boo had always done speeches, apparently that ability didn’t carry over. “… but… you guys still need a king; I could still be that if everyone’s all right with it.”

He could just about kick himself for how he’d worded that, making it almost sound like a meek request. _But_ their opinion was important, he’d never had to enforce his rule with violence and wouldn’t do so now. If they didn’t want him as their ruler anymore, he’d just have to deal with it.

The crowd erupted into more talking. Everyone was concerned and wanted to have a say about something or ask a question. None of it was helpful though, especially with it all being thrown out at once.

“You have a month to decide if you still think I’m fit to rule, then we’ll hold a vote.” He had to use to magic to make his voice louder now so he could be heard over the crowd. “For now, I have some stuff I need to attend to privately.”

And with that, he fled. He tried to disguise it as merely leaving but… he was fleeing and he _hated_ it. He had a lot to think about though, the kind best done in private. Like who was he now? Was Mario still his brother? E. Gadd his friend? What about his boos, did he still have a right to be their king when he was only half dead? What did he even _want_ now? He didn’t know but he intended to find out.

**Notes for the Chapter:**

> First off, thank you so much to everyone who's commented. This story has meant a lot to me and I'm really proud of it so I'm super glad people are enjoying and are invested in it, so thank you for letting me know those things. :)
> 
> Second, I thought long and hard about doing two endings; this one and one where the KBE works and they're free. I decided to just go with this one because it's what felt the most right for the story. However if y'all want me to, I could see what I can do about writing an alternate happy ending too. It wouldn't be much of a bother at all, I do have some pretty solid ideas for one.
> 
> And third, I might already be writing a thing that leads to a happier ending. It's a split path thing though, not an alternate ending. It splits at the end of part 1 and goes in a drastically different direction. I don't know when it'll be done though because I only have the 1st chapter written and I have no clue how long it's gonna be because I have no clue what all even happens in it. So that's gonna be a thing maybe eventually, we'll see.


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